The following lists only preprints without a corresponding final revised paper.
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02 Jan 2025
The helix wake and its properties: reduced order modeling through dynamic mode decomposition
Claudia Muscari, Paolo Schito, Axelle Viré, Alberto Zasso, and Jan-Willem van Wingerden
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-149, https://doi.org/10.5194/wes-2024-149, 2025
Preprint under review for WES (discussion: open, 1 comment)
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This paper presents the findings of a study aimed at describing the flow system downstream of a wind turbine operated with a novel control technology. Results from heavy high-fidelity simulations are used to obtain a low-fidelity model that is quick enough to be used for the optimization of such technologies. Additionally, we were able to retrieve an improved understanding of the physics of such systems under different inflow conditions.
19 Dec 2024
Developing an atlas of rain-induced leading edge erosion for wind turbine blades in the Dutch North Sea
Marco Caboni and Gerwin van Dalum
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-174, https://doi.org/10.5194/wes-2024-174, 2024
Preprint under review for WES (discussion: open, 0 comments)
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Weather simulations carried out over a decade showed that the average erosivity of rainfall on wind turbine blades increases from the southwestern part of the Dutch North Sea to the northeastern region. These results suggest that future wind farms developed in the northeast are likely to encounter higher erosion rates compared to those currently operating in the southwest. This requires special attention when developing mitigation strategies.
19 Dec 2024
Estimating microplastics emissions from offshore wind turbine blades in the Dutch North Sea
Marco Caboni, Anna Elisa Schwarz, Henk Slot, and Harald van der Mijle Meijer
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-175, https://doi.org/10.5194/wes-2024-175, 2024
Preprint under review for WES (discussion: open, 0 comments)
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In this study, we assessed the total quantity of microplastics emitted by wind turbines currently operating in the Dutch North Sea. The estimate of microplastics currently emitted from offshore wind turbines in The Netherlands account for a very small portion of the total microplastics released offshore in The Netherlands, specifically less than one per mille.
18 Dec 2024
Optimal Flight Pattern Debate for Airborne Wind Energy Systems: Circular or Figure-of-eight?
Dylan Eijkelhof, Nicola Rossi, and Roland Schmehl
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-139, https://doi.org/10.5194/wes-2024-139, 2024
Preprint under review for WES (discussion: open, 0 comments)
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This study compares circular and figure-of-eight flight shapes for flying kite wind energy systems, assessing power output, stability, and system lifespan. Results show that circular patterns are ideal for maximizing energy in compact areas, while figure-of-eight paths, especially flying up in the centre of the figure, deliver smoother, more consistent power and have a longer expected kite lifespan. These findings offer valuable insights to enhance design and performance of kite systems.
12 Dec 2024
Brief communication: A note on the variance of wind speed and turbulence intensity
Cristina Lozej Archer
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-159, https://doi.org/10.5194/wes-2024-159, 2024
Preprint under review for WES (discussion: open, 4 comments)
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Two approximate analytical expressions are derived, one for the variance of wind speed and the other for turbulence intensity, based on one simple assumption: that the turbulent fluctuations of the wind are small with respect to the mean. The formulations perform well when applied to the observations from the VERTEX field campaign conducted in 2016.
10 Dec 2024
Building a Diverse and Equitable Distributed Wind Workforce: A Strategic Approach to Collaborator Selection
Kendall Parker, Kamila Kazimierczuk, Micah Taylor, Danielle Preziuso, and Andrew White
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-145, https://doi.org/10.5194/wes-2024-145, 2024
Preprint under review for WES (discussion: open, 0 comments)
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Distributed wind (DW) faces a growing demand for skilled workers, but hiring challenges persist, and workforce development efforts lag behind other wind sectors. This project uses an equity-driven rubric and spatial mapping to identify institutions in disadvantaged areas with strong potential for wind energy training partnerships. The results highlight the rubric as a strategic tool for identifying DW workforce collaborators.
10 Dec 2024
Enhancing minute-scale lidar-based power forecasts of offshore wind farms towards an operational use
Frauke Theuer, Janna Kristina Seifert, Jörge Schneemann, and Martin Kühn
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-141, https://doi.org/10.5194/wes-2024-141, 2024
Preprint under review for WES (discussion: open, 0 comments)
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To be useful for end-users the forecast horizon of lidar-based minute-scale forecasts needs to be extended to at least 15 minutes. In this work, we adapt a lidar-based forecasting methodology to predict wind speed and power with horizons of up to 30 minutes. We found that the skill of the lidar-based approach highly depends on atmospheric conditions and the forecast characteristics. It was able to outperform persistence up to a 16 minute forecast horizon during unstable conditions.
09 Dec 2024
Evaluating the ability of the operational High Resolution Rapid Refresh model version 3 (HRRRv3) and version 4 (HRRRv4) to forecast wind ramp events in the US Great Plains
Laura Bianco, Reagan Mendeke, Jake Lindblom, Irina V. Djalalova, David D. Turner, and James M. Wilczak
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-133, https://doi.org/10.5194/wes-2024-133, 2024
Preprint under review for WES (discussion: open, 1 comment)
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Including more renewable energy into the electric grid is a critical part of the strategy to mitigate climate change. Reliable numerical weather prediction (NWP) models need to be able to predict the intrinsic nature of weather-dependent resources, such as wind ramp events, as wind energy could quickly be available in abundance or temporarily cease to exist. We assess the ability of the operational High Resolution Rapid Refresh NWP model to forecast wind ramp events in two most recent versions.
09 Dec 2024
A small-scale and autonomous testbed for three-line delta kites applied to airborne wind energy
Francisco DeLosRíos-Navarrete, Jorge González-García, Iván Castro-Fernández, and Gonzalo Sánchez-Arriaga
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-170, https://doi.org/10.5194/wes-2024-170, 2024
Preprint under review for WES (discussion: open, 3 comments)
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This work presents a small-scale machine capable of flying delta kites with 3 lines for Airborne Wind Energy research, that is, the extraction of energy from high-altitude winds using aircraft. Its built-in controller allows it to operate autonomously, demonstrated by two test flights which are presented and compared. Additionally, the results obtained by the analysis of the data will help to further improve the control and better understand the behavior of these devices.
09 Dec 2024
Modeling the effects of active wake mixing on wake behavior through large scale coherent structures
Lawrence Cheung, Gopal Yalla, Prakash Mohan, Alan Hsieh, Kenneth Brown, Nathaniel deVelder, Daniel Houck, and Marc Henry de Frahan
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-155, https://doi.org/10.5194/wes-2024-155, 2024
Preprint under review for WES (discussion: open, 0 comments)
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Mitigating turbine wakes is an important aspect to maximizing wind farm energy production but is a challenge to model. We demonstrate a new approach to modeling active wake mixing, which re-energizes turbine wake through periodic blade pitching. The new model divides the wake into separate steady, unsteady, and turbulent components, and solves for each in a computationally efficient manner. Our results show the model can reasonably predict the faster wake recovery due to mixing.
03 Dec 2024
A scaling methodology for the Hybrid-Lambda Rotor – Characterization and validation in wind tunnel experiments
Daniel Ribnitzky, Vlaho Petrovic, and Martin Kühn
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-168, https://doi.org/10.5194/wes-2024-168, 2024
Preprint under review for WES (discussion: open, 1 comment)
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In this paper, the Hybrid-Lambda Rotor is scaled to wind tunnel size and validated in wind tunnel experiments. The objectives are to derive a scaling methodology, to investigate the influence of the steep gradients of axial induction along the blade span and to characterize the near wake. The study reveals complex three-dimensional flow patterns for blade designs with non-uniform loading and it can offer new inspirations when solving other scaling problems for complex wind turbine systems.
02 Dec 2024
Comparison of wind-farm control strategies under realistic offshore wind conditions: turbine quantities of interest
Joeri A. Frederik, Eric Simley, Kenneth A. Brown, Gopal R. Yalla, Lawrence C. Cheung, and Paul A. Fleming
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-164, https://doi.org/10.5194/wes-2024-164, 2024
Preprint under review for WES (discussion: final response, 2 comments)
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In this paper, we present results from advanced computer simulations to determine the effects of applying different control strategies to a small wind farm. We show that when there is variability in wind direction over height, steering the wake of a turbine away from other turbines is the most effective strategy. When this variability is not present, actively changing the pitch angle of the blades to increase turbulence in the wake could be more effective.
02 Dec 2024
Improved coupling between an atmospheric LES and an aeroelastic code for the simulation of wind turbines under heterogeneous inflow
Sonja Steinbrück, Thorben Eilers, Lukas Vollmer, Kerstin Avila, and Gerald Steinfeld
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-146, https://doi.org/10.5194/wes-2024-146, 2024
Preprint under review for WES (discussion: open, 0 comments)
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This paper introduces an enhanced coupling between the LES code PALM and the aeroelastic code FAST, enabling detailed turbine output in temporally and spatially heterogeneous atmospheric flows while maintaining computational efficiency. A wind speed correction is added to reduce errors from force smearing on the numerical grid. Results were evaluated through comparisons between different model setups and turbine measurements, including assessments in a two-turbine wake situation.
27 Nov 2024
Deep mining of megawatt large wind turbine actual operating data: exploration of accurate modeling & performance optimization
Weimin Wu, Xiongfei Liu, Yu Ren, Suocheng Zhang, Wanjun Yan, and Wenqiang Du
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-163, https://doi.org/10.5194/wes-2024-163, 2024
Preprint under review for WES (discussion: final response, 5 comments)
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The real-time operation data analysis and condition monitoring of large wind turbines are crucial for ensuring the efficient and safe operation of wind farms. In response to this, this paper proposes a precise prediction model architecture based on the multivariate linear regression algorithm to gain a deeper understanding of the actual operation of large wind turbines.
27 Nov 2024
Obtaining fatigue-based frequency domain specifications for the design of controllers in wind turbines
Irene Miquelez-Madariaga, Jesús Arellano, Daniel Lacheta-Lecumberri, and Jorge Elso
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-154, https://doi.org/10.5194/wes-2024-154, 2024
Preprint under review for WES (discussion: open, 1 comment)
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This paper presents a method for obtaining mechanical fatigue estimations from linear models and fatigue-based specifications for the design of controllers for wind turbines. The method is validated by the design of controllers for a 15 MW reference wind turbine. The error in the fatigue estimation is smaller than 2 % and fatigue loads are successfully reduced.
27 Nov 2024
Gaussian Mixture autoencoder for uncertainty-aware damage identification in a Floating Offshore Wind Turbine
Ana Fernandez-Navamuel, Nicolas Gorostidi, David Pardo, Vincenzo Nava, and Eleni Chatzi
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-160, https://doi.org/10.5194/wes-2024-160, 2024
Preprint under review for WES (discussion: open, 2 comments)
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This work employs Deep Neural Networks to identify damage in the mooring system of a Floating Offshore Wind Turbine (FOWT) using measurements from the platform response. We account for the effect of uncertainty in the assessment estimates caused by the existence of multiple solutions (different damage scenarios can cause the observed data). We describe the damage condition features using a distributional model based on a Gaussian Mixture, which captures the uncertainty in the predictions.
26 Nov 2024
Investigating the Relationship between Simulation Parameters and Flow Variables in Simulating Atmospheric Gravity Waves for Wind Energy Applications
Mehtab Ahmed Khan, Dries Allaerts, Simon J. Watson, and Matthew J. Churchfield
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-138, https://doi.org/10.5194/wes-2024-138, 2024
Preprint under review for WES (discussion: open, 1 comment)
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To guide realistic atmospheric gravity wave simulations, we conduct an LES study of flow over a 2D hill and through a wind farm canopy, examining optimal domain size and Rayleigh damping layer setup. Wave properties based on a Froude number determine optimal domain and damping parameters. Reasonably accurate solutions require the domain length exceed the effective horizontal wavelength, height and damping thickness equal a vertical wavelength, and normalized-damping coefficient between 1–10.
26 Nov 2024
System design and scaling trends for airborne wind energy
Rishikesh Joshi, Dominic von Terzi, and Roland Schmehl
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-161, https://doi.org/10.5194/wes-2024-161, 2024
Preprint under review for WES (discussion: final response, 3 comments)
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This paper presents a methodology for system design of airborne wind energy (AWE). A multi-disciplinary design, analysis, and optimization (MDAO) framework was developed, integrating power, energy production, and cost models for fixed-wing ground-generation (GG) AWE systems. Using the levelized cost of electricity (LCoE) as the design objective, we found that the optimal size of systems lies between the rated power of 100 kW and 1000 kW.
26 Nov 2024
A parcel-level evaluation of distributed wind opportunity in the contiguous United States
Jane Lockshin, Paula Pérez, Slater Podgorny, Michaela Sizemore, Paritosh Das, Jeffrey D. Laurence-Chasen, Paul Crook, and Caleb Phillips
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-147, https://doi.org/10.5194/wes-2024-147, 2024
Preprint under review for WES (discussion: final response, 3 comments)
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This study examines the potential for distributed wind energy across the contiguous United States by leveraging a novel modeling approach that utilizes a high-resolution dataset and analyzes over 150 million parcels. Modeling results reveal substantial opportunities for energy generation using distributed wind technologies. Additionally, findings reveal a substantial increase from prior modeling results in estimated technical and economic potential for distributed wind.
25 Nov 2024
Identification of Natural and Anthropogenic Hazards within Mid-Atlantic Bight For The Purpose of Offshore Wind Turbine Foundation Recommendations
Ophelia Persephone Christoph and John Madsen
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-157, https://doi.org/10.5194/wes-2024-157, 2024
Preprint under review for WES (discussion: open, 2 comments)
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The paper explores the critical factors affecting offshore wind development in the Mid-Atlantic Bight Central Atlantic Call Area, focusing on the natural and human-made hazards. By analyzing geological studies, it identifies significant geological elements like paleochannels, sand ridges, and sediment variability, emphasizing the challenges posed by sediment type that impacts foundation stability.
25 Nov 2024
A dynamic open-source model to investigate wake dynamics in response to wind farm flow control strategies
Marcus Becker, Maxime Lejeune, Philippe Chatelain, Dries Allaerts, Rafael Mudafort, and Jan-Willem van Wingerden
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-150, https://doi.org/10.5194/wes-2024-150, 2024
Preprint under review for WES (discussion: open, 0 comments)
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Established turbine wake models are steady-state. This paper presents an open-source dynamic wake modeling framework that compliments established steady-state wake models with dynamics. It is advantageous over steady-state wake models to describe wind farm power and energy over shorter periods. The model enables researchers to investigate the effectiveness of wind farm flow control strategies. This leads to a better utilization of wind farms and allows their use to the full extent.
25 Nov 2024
Leveraging Signal Processing and Machine Learning for Automated Fault Detection in Wind Turbine Drivetrains
Faras Jamil, Cédric Peeters, Timothy Verstraeten, and Jan Helsen
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-114, https://doi.org/10.5194/wes-2024-114, 2024
Preprint under review for WES (discussion: final response, 3 comments)
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A hybrid fault detection method is proposed, which combines physical domain knowledge with machine learning models to automatically detect mechanical faults in wind turbine drivetrain components. It offers detailed insights for experts while giving operators a high-level overview of the machine's health to assist in planning effective maintenance strategies. It was validated on multiple years of wind farm data and the potential faults were accurately predicted, which was confirmed by experts.
21 Nov 2024
A multi-objective Economic Nonlinear Model Predictive Controller for Power and Platform Motion on Floating Offshore Wind Turbines
Luca Pustina, Francesco Biral, Enrico Bertolazzi, and Jacopo Serafini
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-144, https://doi.org/10.5194/wes-2024-144, 2024
Preprint under review for WES (discussion: final response, 4 comments)
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The use of advanced nonlinear controllers is proposed as a way to improve the power output of floating offshore wind turbines and reduce platform motion simultaneously. The analysis has shown that an optimal frontier exists when considering the two objectives and that the load on pitch actuators remains reasonable. The same methodology may be applied to other composite objectives including, for example, generated power quality.
20 Nov 2024
Evaluating mesoscale model predictions of diurnal speedup events in the Altamont Pass Wind Resource Area of California
Robert S. Arthur, Alex Rybchuk, Timothy W. Juliano, Gabriel Rios, Sonia Wharton, Julie K. Lundquist, and Jerome D. Fast
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-137, https://doi.org/10.5194/wes-2024-137, 2024
Preprint under review for WES (discussion: final response, 2 comments)
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This paper evaluates a new model configuration for wind energy forecasting in complex terrain. We compare model results to observations in the Altamont Pass (California, USA), where wind channeling through a mountain pass leads to increased energy production. We show evidence of improved wind speed and turbulence predictions compared to a more established modeling approach. Our work helps to ensure the robustness of the new model configuration for future wind energy applications.
20 Nov 2024
COFLEX: A novel set point optimiser and feedforward-feedback control scheme for large flexible wind turbines
Guido Lazzerini, Jacob Deleuran Grunnet, Tobias Gybel Hovgaard, Fabio Caponetti, Vasu Datta Madireddi, Delphine De Tavernier, and Sebastiaan Paul Mulders
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-151, https://doi.org/10.5194/wes-2024-151, 2024
Preprint under review for WES (discussion: open, 1 comment)
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Large wind turbines face design challenges due to increased flexibility of blades. Conventional control strategies fail under large deformations, impacting performance. We present COFLEX, a feedforward-feedback control scheme, addressing flexibility and overcoming the limitations of conventional strategies. By testing it on the IEA 15 MW turbine with realistic wind conditions, we demonstrated improvements to power by up to 5 %, while constraining blade deflections.
19 Nov 2024
Operational wind plants increase planetary boundary layer height: An observational study
Aliza Abraham, Matteo Puccioni, Arianna Jordan, Emina Maric, Nicola Bodini, Nicholas Hamilton, Stefano Letizia, Petra M. Klein, Elizabeth Smith, Sonia Wharton, Jonathan Gero, Jamey D. Jacob, Raghavendra Krishnamurthy, Rob K. Newsom, Mikhail Pekour, and Patrick Moriarty
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-148, https://doi.org/10.5194/wes-2024-148, 2024
Preprint under review for WES (discussion: open, 0 comments)
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This study is the first to use real-world atmospheric measurements to show that large wind plants can increase the height of the planetary boundary layer, the part of the atmosphere near the surface where life takes place. The planetary boundary layer height governs processes like pollutant transport and cloud formation, and is a key parameter for modeling the atmosphere. The results of this study provide important insights into interactions between wind plants and their local environment.
19 Nov 2024
Life Cycle Assessment of New Jersey Offshore Wind
Meghann Smith, Nawal Shoaib, and Pankaj Lal
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-143, https://doi.org/10.5194/wes-2024-143, 2024
Preprint under review for WES (discussion: open, 0 comments)
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This research estimates the environmental impact of New Jersey offshore wind under a domestic supply chain using life cycle assessment modelling.
15 Nov 2024
Experimental Validation of Parked Loads for a Floating Vertical Axis Wind Turbine: Wind-Wave Basin Tests
Md Sanower Hossain and D. Todd Griffith
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-156, https://doi.org/10.5194/wes-2024-156, 2024
Preprint under review for WES (discussion: final response, 2 comments)
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The document presents an experimental study on the parked loads of floating vertical axis wind turbines (VAWTs) in a wind and waves basin, focusing on the effects of wind speed, solidity, and floating platform dynamics. Findings show that higher wind speed, and higher solidity generally increase the parked loads, while a floating platform introduces additional effects due to tilting. A semi-numerical model was also presented to predict the parked loads, which helps enhance VAWT design.
15 Nov 2024
Analysis and calibration of optimal power balance rotor-effective wind speed estimation schemes for large-scale wind turbines
Atindriyo Kusumo Pamososuryo, Fabio Spagnolo, and Sebastiaan Paul Mulders
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-158, https://doi.org/10.5194/wes-2024-158, 2024
Preprint under review for WES (discussion: final response, 3 comments)
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As wind turbines grow in size, measuring wind speed accurately becomes harder, impacting their performance. Traditional sensors cannot capture wind variations across large rotor areas. To address this, a new method is developed to estimate wind speed accurately, accounting for these variations. Using mid-fidelity simulations, our approach showed better tracking, noise resilience, and easy tuning for different turbine sizes.
15 Nov 2024
Wake Development in Floating Wind Turbines: New Insights and Open Dataset from Wind Tunnel Experiments
Alessandro Fontanella, Alberto Fusetti, Stefano Cioni, Francesco Papi, Sara Muggiasca, Giacomo Persico, Vincenzo Dossena, Alessandro Bianchini, and Marco Belloli
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-140, https://doi.org/10.5194/wes-2024-140, 2024
Preprint under review for WES (discussion: final response, 5 comments)
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The article investigates the impact of large movements allowed by floating wind turbine foundations on their aerodynamics and wake behavior. Wind tunnel tests with a model turbine reveal that platform motions affect wake patterns and turbulence levels. Insights from these experiments are crucial for optimizing large-scale floating wind farms. The dataset obtained from the experiment is published and can aid in developing simulation tools for floating wind turbines.
14 Nov 2024
Offshore Wind Farm Layout Optimization Accounting for Participation to Secondary Reserve Markets
Thuy-Hai Nguyen, Julian Quick, Pierre-Elouan Réthoré, Jean-François Toubeau, Emmanuel De Jaeger, and François Vallée
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-131, https://doi.org/10.5194/wes-2024-131, 2024
Preprint under review for WES (discussion: open, 0 comments)
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Current offshore wind farms have been designed to maximize their production of electricity at all times, and not to keep some reserve power in case of unexpected events on the grid. We present a new formulation for designing wind farms to maximize revenues from both energy and reserve markets. It is applied on a real-life wind farm. We show that profits are expected to increase in a significant way for wind farms designed and operated for reserve, with less energy supplied.
07 Nov 2024
Coleman free aero-elastic stability methods for three- and two-bladed floating wind turbines
Bogdan Pamfil, Henrik Bredmose, and Taeseong Kim
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-136, https://doi.org/10.5194/wes-2024-136, 2024
Preprint under review for WES (discussion: open, 2 comments)
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A floating wind turbine time domain model, that considers dynamic stall, is used to develop Coleman free aero-elastic stability analysis methods, namely Hill's and Floquet's. We clarify how the floater tilt is involved in the stability analysis, show damping effects of aerodynamic states, prove that results of both methods agree and can reproduce the forward and backward whirling rotor modes in a Coleman-based analysis, and demonstrate that both methods can be applied to a two-bladed rotor.
07 Nov 2024
Analyzing the performance of vertical wind profilers in rain events
Adriel J. Carvalho, Francisco Albuquerque Leite Neto, and Denisson Q. Oliveira
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-132, https://doi.org/10.5194/wes-2024-132, 2024
Preprint under review for WES (discussion: final response, 2 comments)
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The wind profilers are very important to wind power industry since they can capture wind velocity and direction at higher altitudes. Although there are some literature investigating their performance in different scenarios, this paper covers a gap investigating and comparing their performance under rain events. This investigation is important since the data collected support strategic decisions in wind power industry, demanding a high availability in all situations.
05 Nov 2024
A listening experiment exploring the relationship between noise annoyance and sound quality metrics for airborne energy systems
Helena Schmidt, Renatto M. Yupa-Villanueva, Daniele Ragni, Roberto Merino-Martínez, Piet van Gool, and Roland Schmehl
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-125, https://doi.org/10.5194/wes-2024-125, 2024
Preprint under review for WES (discussion: open, 2 comments)
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This study investigates noise annoyance caused by airborne wind energy systems (AWESs), a novel wind energy technology that uses kites to harness high-altitude winds. Through a listening experiment with 75 participants, sharpness was identified as the key factor predicting annoyance. Fixed-wing kites generated more annoyance than soft-wing kites, likely due to their sharper, more tonal sound. The findings can help improve AWESs’ designs, reducing noise-related disturbances for nearby residents.
04 Nov 2024
Quantifying Tropical Cyclone-Generated Waves in Extreme-Value-Derived Design for Offshore Wind
Sarah McElman, Amrit Verma, and Andrew Goupee
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-129, https://doi.org/10.5194/wes-2024-129, 2024
Preprint under review for WES (discussion: final response, 5 comments)
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This paper investigates how tropical cyclones are represented in metocean models and statistics applied to offshore wind design. It provides recommendations for ensuring the accurate representation of extreme waves for design and operation of offshore projects on the Atlantic coast of the USA.
29 Oct 2024
Backup power supply for a hydrogen-producing offshore wind turbine – a technology comparison
Linus Niklaus, Paul Rothe, Johannes Liebertseder, and Martin Doppelbauer
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-135, https://doi.org/10.5194/wes-2024-135, 2024
Preprint under review for WES (discussion: open, 2 comments)
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Both fuel cells and combustion engines can be used to supply hydrogen-producing offshore wind turbines with electrical energy in the event of a wind outage. A simulative comparison in combination with a qualitative assessment considering the maritime boundary conditions showed that the combination of an internal combustion engine and a battery storage system is the most suitable for this purpose. This system provides high energy efficiency with the necessary robustness on the high seas.
28 Oct 2024
An analytical formulation for turbulent kinetic energy added by wind turbines based on large-eddy simulation
Ali Khanjari, Asim Feroz, and Cristina Archer
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-128, https://doi.org/10.5194/wes-2024-128, 2024
Preprint under review for WES (discussion: final response, 2 comments)
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Wind turbines add turbulence to the atmosphere behind them, especially 4–6 diameters downstream and near the rotor top. We propose an equation that predicts the distribution of added turbulence as a function of a turbine parameter (thrust coefficient) and an atmospheric parameter (undisturbed turbulence intensity before the turbine). We find that our equation performs well, although not perfectly. Eventually this equation can be used to better understand how wind turbines affect the atmosphere.
28 Oct 2024
Gulf of Mexico Hurricane Risk Assessment for Offshore Wind Energy Sites
Lauren A. Mudd and Peter J. Vickery
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-123, https://doi.org/10.5194/wes-2024-123, 2024
Preprint under review for WES (discussion: open, 2 comments)
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This research presents an assessment of hurricane risk to offshore wind turbine systems in the Gulf of Mexico. Hurricanes that frequent this area can potentially exceed design limits prescribed by the International Electrotechnical Commission (IEC) wind design standards. Translations between the well-established Saffir-Simpson scale and the IEC design classes were developed to convert to communicate of hurricane severity in terms of design load conditions familiar to wind turbine designers.
22 Oct 2024
Sensitivity analysis of numerical modeling input parameters on floating offshore wind turbine loads in extreme idling conditions
Will Wiley, Jason Jonkman, and Amy Robertson
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-130, https://doi.org/10.5194/wes-2024-130, 2024
Preprint under review for WES (discussion: final response, 2 comments)
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Numerical models, used to assess loads on floating offshore wind turbines, require many input parameters to describe air and water conditions, system properties, and load calculations. All parameters have some possible range, due to uncertainty and/or variations with time. The selected values can have important effects on the uncertainty in the resulting loads. This work identifies the input parameters that have the most impact on ultimate and fatigue loads for extreme storm load cases.
17 Oct 2024
Wind farm layout optimization with alignment constraints
Paul Malisani, Tristan Bartement, and Pauline Bozonnet
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-118, https://doi.org/10.5194/wes-2024-118, 2024
Preprint under review for WES (discussion: open, 1 comment)
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Maritime authorities often impose turbine alignment constraints on developers to secure the navigation of boats within the wind farm, potentially creating substantial wake losses. The proposed contribution is a new Wind Farm Layout Optimization (WFLO) algorithm that considers these constraints. The proposed method optimizes the grid-alignment parameters and the turbines' location on this grid. We illustrate the algorithm's performances on a challenging example.
17 Oct 2024
Near wake behavior of an asymmetric wind turbine rotor
Pin Chun Yen, Wei Yu, and Fulvio Scarano
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-122, https://doi.org/10.5194/wes-2024-122, 2024
Preprint under review for WES (discussion: final response, 2 comments)
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This study explores how changing wind turbine blade length affects airflow behind the turbine. Using high- and low-fidelity simulations, we found that varying blade lengths accelerate wake interactions but don’t improve flow recovery or energy capture. Turbulence plays a bigger role in breaking up airflow patterns than rotor asymmetry. These findings provide insights for designing more efficient wind turbines.
15 Oct 2024
Spatial development of planar and axisymmetric wakes of porous objects under a pressure gradient: a wind tunnel study
Wessel van der Deijl, Martin Obligado, Stéphane Barre, and Christophe Sicot
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-116, https://doi.org/10.5194/wes-2024-116, 2024
Revised manuscript under review for WES (discussion: final response, 4 comments)
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We present a wind tunnel study on the effect of an adverse pressure gradient on wakes from porous disks and cylinders. We have quantified the spatial development of the turbulent wakes for Reynolds numbers up to 3.9 × 105 and at distances ranging from 1 to 12 diameters downstream, both with and without a pressure gradient. Consistently with previous studies, we find that the pressure gradient has an effect in all cases, resulting in larger velocity deficits and wider wakes.
14 Oct 2024
Multi-task Learning Long Short-term Memory Model to Emulate Wind Turbine Blade Dynamics
Shubham Baisthakur and Breiffni Fitzgerald
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-105, https://doi.org/10.5194/wes-2024-105, 2024
Preprint under review for WES (discussion: open, 1 comment)
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Site-specific performance analysis of wind turbines is crucial but computationally prohibitive due to the high cost of evaluating numerical models. To address this, the authors propose a machine learning model combined with dimensionality reduction using Principal Component Analysis and Discrete Cosine Transform, along with a Long Short-Term Memory model, to predict dynamic responses at a fraction of the computational cost.
11 Oct 2024
Design of a two-bladed counterpart to the three-bladed INNWIND 20 MW offshore reference wind turbine
Fabian Anstock, Marcel Schütt, and Vera Schorbach
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-121, https://doi.org/10.5194/wes-2024-121, 2024
Preprint under review for WES (discussion: open, 2 comments)
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Large offshore wind turbines with only two blades possess the potential to reduce the current cost of energy. Yet, this still has to be validated by direct comparisons to a very similar standard three-bladed wind turbine, which is challenging due to the notorious difficulty of establishing equivalent designs of such complex systems. This paper finally presents a methodology to transform a three-bladed turbine into its most similar two-bladed counterpart and provides valuable lessons learned.
10 Oct 2024
Numerical Investigation of Regenerative Wind Farms Featuring Enhanced Vertical Energy Entrainment
YuanTso Li, Wei Yu, Andrea Sciacchitano, and Carlos Ferreira
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-124, https://doi.org/10.5194/wes-2024-124, 2024
Revised manuscript under review for WES (discussion: final response, 3 comments)
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A novel wind farm concept, called a regenerative wind farm, is investigated numerically. This concept addresses the significant wake interaction losses among the traditional wind farms. Our results show that regenerative wind farms can greatly reduce these losses, boosting power output per unit land. Unlike traditional farms with 3-bladed wind turbines, regenerative farms use Multi-Rotor Systems with Lifting devices (MRSL), and it is this unconventional design effectively reduces wake losses.
08 Oct 2024
Integer programming for optimal yaw control of wind farms
Felix Bestehorn, Florian Bürgel, Christian Kirches, Sebastian Stiller, and Andreas M. Tillmann
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-120, https://doi.org/10.5194/wes-2024-120, 2024
Preprint under review for WES (discussion: final response, 3 comments)
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Wind turbines organized in wind farms are an important electric power source. Thereby, each wind turbine causes a so-called wake with a reduced wind speed. This can influence following wind turbines and is an opportunity to optimize the operation of the complete wind farm, i.e., we steer the wakes to increase the total power output of the wind farm. In order to do this efficiently, we exploit repetitive structures within a wind farm.
08 Oct 2024
The optimum range of design axial induction factors for lowest levelized-cost of energy
Desirae Major and Sven Schmitz
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-109, https://doi.org/10.5194/wes-2024-109, 2024
Manuscript not accepted for further review (discussion: closed, 3 comments)
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The present work proposes a novel design methodology for increasingly large-diameter offshore wind turbines that includes a measure of cost/fatigue, representing a paradigm shift away from design methods for pure power maximization. Results of the research indicate that notable cost of energy reductions can be achieved for a given wind turbine power rating. The achievable reduction in cost of energy from this novel design methodology will keep wind cost-competitive in the global energy market.
02 Oct 2024
Performance of wind assessment datasets in United States coastal areas
Lindsay M. Sheridan, Jiali Wang, Caroline Draxl, Nicola Bodini, Caleb Phillips, Dmitry Duplyakin, Heidi Tinnesand, Raj K. Rai, Julia E. Flaherty, Larry K. Berg, Chunyong Jung, and Ethan Young
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-115, https://doi.org/10.5194/wes-2024-115, 2024
Revised manuscript under review for WES (discussion: final response, 4 comments)
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Three recent wind resource datasets are assessed for their skills in representing annual average wind speeds and seasonal, diurnal, and inter-annual trends in the wind resource to support customers interested in small and midsize wind energy.
02 Oct 2024
Tall Wind Profile Validation Using Lidar Observations and Hindcast Data
Etienne Cheynet, Jan Markus Diezel, Hilde Haakenstad, Øyvind Breivik, Alfredo Peña, and Joachim Reuder
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-119, https://doi.org/10.5194/wes-2024-119, 2024
Preprint under review for WES (discussion: final response, 3 comments)
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This study aims to help future large offshore wind turbines and airborne wind energy systems by providing insights into wind speeds at much higher altitudes than previously examined. We assessed three wind models (ERA5, NORA3, and NEWA) to predict wind speeds up to 500 m. Using lidar data from Norway and the North Sea, we found that ERA5 excels offshore, while NORA3 performs best onshore. However, the performance of the models depends on the locations and the evaluation criteria.
30 Sep 2024
Glauert's Optimum Rotor Disk Revisited – A Calculus of Variations Solution and Exact Integrals for Thrust and Bending Moment Coefficients
Divya Tyagi and Sven Schmitz
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-111, https://doi.org/10.5194/wes-2024-111, 2024
Revised manuscript accepted for WES (discussion: closed, 4 comments)
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This paper adds to the literature on rotor disk theory by solving the century-old problem with a different mathematical approach. The classical results are recovered, while also adding expressions and asymptotic limits for performance coefficients that were not included in the original theory. This work adds to classical rotor disk theory as a valuable contribution to research and teaching in wind turbine aerodynamics.
25 Sep 2024
IMAP-WFO: A holistic optimization tool for bottom fixed offshore wind farm design and control
Niels Roeders, Matteo Capaldo, Sander van Nederveen, and Oriol Colomés
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-117, https://doi.org/10.5194/wes-2024-117, 2024
Revised manuscript under review for WES (discussion: final response, 3 comments)
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Offshore wind farms face the challenge of optimization among many parameters influencing key performance indicators. This research introduces a novel farm optimization framework that enhances flexibility, accuracy, and uncertainty quantification in offshore wind farm design and operation. The proposed work has the key innovation in the ability to translate technical functions into socio-economic objectives, where stakeholders can dynamically weigh these objectives based on their preferences.
23 Sep 2024
Spatio-Temporal Graph Neural Networks for Power Prediction in Offshore Wind Farms Using SCADA Data
Simon Daenens, Timothy Verstraeten, Pieter-Jan Daems, Ann Nowé, and Jan Helsen
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-113, https://doi.org/10.5194/wes-2024-113, 2024
Preprint under review for WES (discussion: final response, 2 comments)
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This study presents a novel model for predicting wind turbine power output at high temporal resolution in wind farms using a hybrid Graph Neural Network (GNN) and Long Short-Term Memory (LSTM) architecture. By modeling the wind farm as a graph, the model captures both spatial and temporal dynamics, outperforming traditional power curve methods. Integrated within a Normal Behavior Model (NBM) framework, the model effectively identifies and analyzes power loss events.
18 Sep 2024
A large-eddy simulation analysis of collective wind-farm axial-induction control in the presence of blockage
Théo Delvaux and Johan Meyers
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-110, https://doi.org/10.5194/wes-2024-110, 2024
Revised manuscript under review for WES (discussion: final response, 4 comments)
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The work explores the potential for wind farm load reduction and power maximization. We carried out a series of high-fidelity wind farm simulations (LES) for a wide variety of atmospheric conditions and operating regimes. Because of turbine-scale interactions and large-scale effects, we observed that the optimal wind farm operating point is reached at lower regimes. Therefore, we proposed three simple approaches with which thrust significantly decreases with only limited impact on power.
10 Sep 2024
Direct integration of non-axisymmetric Gaussian wind-turbine wake including yaw and wind-veer effects
Karim Ali, Pablo Ouro, and Tim Stallard
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-107, https://doi.org/10.5194/wes-2024-107, 2024
Preprint under review for WES (discussion: final response, 3 comments)
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We introduce an innovative analytical method to better understand and optimize wind farm performance by accurately calculating how turbine wakes affect each other. Unlike traditional numerical approaches, our method provides a precise way to measure the impact of upstream wakes on downstream turbines. This new approach, validated through numerical comparisons, enhances optimisation strategies, potentially leading to more efficient wind farm operations and increased power generation.
09 Sep 2024
On the lidar-turbulence paradox and possible countermeasures
Alfredo Peña, Ginka Georgieva Yankova, and Vasiliki Mallini
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-108, https://doi.org/10.5194/wes-2024-108, 2024
Revised manuscript accepted for WES (discussion: closed, 4 comments)
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Lidars are vastly used in wind energy but most users struggle when interpreting lidar turbulence measures. Here we explain why is difficult to convert them into standard measurements. We show two ways to convert lidar to in-situ turbulence measurements, both using neural networks with one of them based on physics while the other is purely data driven. They show promising results when compared to high-quality turbulence measurements from a tall mast.
05 Sep 2024
Modular deep learning approach for wind farm power forecasting and wake loss prediction
Stijn Ally, Timothy Verstraeten, Pieter-Jan Daems, Ann Nowé, and Jan Helsen
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-94, https://doi.org/10.5194/wes-2024-94, 2024
Revised manuscript under review for WES (discussion: final response, 4 comments)
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Wind farms play an important role in the energy transition. Unfortunately, the power production of wind farms can fluctuate heavily and depends on many parameters. It is, however, crucial that there is always an equilibrium between electricity production and consumption. Therefore it is important to have accurate power forecasts. This paper presents a methodology, based on machine learning, to generate better farm power forecasts, enabling better scheduling, trading and balancing of wind energy.
02 Sep 2024
A machine learning-based approach for active monitoring of blades pitch misalignment in wind turbines
Sabrina Milani, Jessica Leoni, Stefano Cacciola, Alessandro Croce, and Mara Tanelli
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-100, https://doi.org/10.5194/wes-2024-100, 2024
Revised manuscript accepted for WES (discussion: final response, 6 comments)
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In this paper, we propose a novel machine-learning framework pitch misalignment detection in wind turbines. By using a minimal set of standard sensors, our method detects misalignments as small as 0.1deg and localizes the affected blades. It combines signal processing with a hierarchical classification structure and linear regression for precise severity quantification. Evaluation results validate the approach, showing notable accuracy in misalignment classification, regression, and localization
30 Aug 2024
Modelling Frontal Low-Level Jets and Associated Extreme Wind Power Ramps over the North Sea
Harish Baki, Sukanta Basu, and George Lavidas
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-99, https://doi.org/10.5194/wes-2024-99, 2024
Revised manuscript under review for WES (discussion: final response, 4 comments)
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Our study explores how frontal low-level jets (FLLJs) impact wind power production by causing ramp-down events. Using the Weather Research and Forecasting model, we analyzed various modeling configurations and found that initial and boundary conditions, domain configuration, and wind farm parameterization significantly influence simulations. Our findings show such extreme events can be forecasted one day in advance, helping manage wind power more efficiently for a stable, reliable energy supply.
27 Aug 2024
A Lightweight Vortex Particle-Mesh Library for Variable-Fidelity Simulation of Wind Turbine Wakes
Joseph Robert Saverin
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-73, https://doi.org/10.5194/wes-2024-73, 2024
Preprint under review for WES (discussion: open, 1 comment)
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The interaction of the wake of a wind turbine with neighboring and downstream turbines in a wind farm can have a significant impact on both energy capture and unsteady turbine loads. The understanding the fluid-dynamic behaviour in the wake therefore has a plethora of important applications. The development of efficient, user-friendly numerical tools to investigate these phenomena is therefore critical to the future simulation of wind farms. In this work, an efficient flow solver is presented.
26 Aug 2024
Large-eddy simulation of an atmospheric bore and associated gravity wave effects on wind farm performance in the Southern Great Plains
Adam S. Wise, Robert S. Arthur, Aliza Abraham, Sonia Wharton, Raghavendra Krishnamurthy, Rob Newsom, Brian Hirth, John Schroeder, Patrick Moriarty, and Fotini K. Chow
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-84, https://doi.org/10.5194/wes-2024-84, 2024
Preprint under review for WES (discussion: final response, 3 comments)
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Wind farms can be subject to rapidly changing weather events. In the United States Great Plains, some of these weather events can result in waves in the atmosphere that ultimately affect how much power a wind farm can produce. We modeled a specific event of waves observed in Oklahoma. We determined how to accurately model the event and analyzed how it affected a wind farm’s power production finding that the waves both decreased power and made it more variable.
20 Aug 2024
Flight guidance concept for the launching and landing phase of a flying wing used in an airborne wind energy system
Dominik Felix Duda, Hendrik Fuest, Tobias Islam, and Dieter Moormann
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-90, https://doi.org/10.5194/wes-2024-90, 2024
Revised manuscript under review for WES (discussion: final response, 10 comments)
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The use of flying wings in AWES is promising. This paper develops a guidance concept for launching and landing of such a flying wing AWES. The fundamental challenges are presented, and a suitable guidance concept identified. It is analyzed in terms of controllability at different wind speeds and guidance parameters. Based on this, a flight regime is identified and a controller is designed. Simulation results show that the control concept facilitates the desired launching and landing.
16 Aug 2024
Mitigation of Power System Oscillations in Wind Farm Integrated Multi-Machine System using PSS and TCSC
Qurratulain, Emad Jamil, Salman Hameed, Rupendra Kumar Pachauri, Baseem Khan, and Ahmed Ali
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-75, https://doi.org/10.5194/wes-2024-75, 2024
Manuscript not accepted for further review (discussion: closed, 2 comments)
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This paper reports the mitigation of power system oscillations by using power system stabilizer aided TCSC. For analyzing the performance of the wind-farm integrated test system, various parameters (line power, bus voltages, rotor angle deviation, active & re-active power) of the test system are observed under random speed variation with different types of faults.
12 Aug 2024
Enabling Efficient Sizing of Hybrid Power Plants: A Surrogate-Based Approach to Energy Management System Modeling
Charbel Assaad, Juan Pablo Murcia Leon, Julian Quick, Tuhfe Göçmen, Sami Ghazouani, and Kaushik Das
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-96, https://doi.org/10.5194/wes-2024-96, 2024
Revised manuscript under review for WES (discussion: final response, 8 comments)
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This research develops a new method for assessing Hybrid Power Plants (HPPs) profitability, combining wind and battery systems. It addresses the need for an efficient, accurate, and comprehensive operational model by approximating a state-of-the-art Energy Management System (EMS) for spot market power bidding using machine learning. The approach significantly reduces computational demands while maintaining high accuracy. It thus opens new possibilities in terms of optimizing the design of HPPs.
12 Aug 2024
Enhancing turbulent fluctuation measurement with tailored wind lidar profilers
Maxime Thiébaut, Frédéric Delbos, Cristina Benzo, Loïc Mahe, and Florent Guinot
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-93, https://doi.org/10.5194/wes-2024-93, 2024
Revised manuscript has not been submitted (discussion: closed, 2 comments)
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This paper explores potential technical enhancements to wind lidar profilers for improved turbulence measurement. The study separately tests the effects of increased sampling rate and reduced probe length against a commercial lidar of the same type. Various turbulence metrics were quantified to evaluate the impact of these technical modifications. The results indicate that increasing the sampling rate is the most valuable enhancement for turbulence measurement.
09 Aug 2024
Spatio-temporal behavior of the far-wake of a wind Turbine model subjected to harmonic motions: Phase averaging applied to Stereo-PIV measurements
Antonin Hubert, Boris Conan, and Sandrine Aubrun
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-95, https://doi.org/10.5194/wes-2024-95, 2024
Revised manuscript under review for WES (discussion: final response, 4 comments)
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The paper aims to study the far-wake of a wind turbine under realistic inflow conditions subjected to harmonic floating motions. The present work show that phase-averaging enables the observation of the coherent spatio-temporal wake behaviour in response to the harmonic motions, on contrary to previous studies with time-averaging, and that the resulting variations of the chosen metrics exhibit an intensity higher than those expected by using basic quasi-steady-state approaches.
30 Jul 2024
State-of-the-art efficiency determination of a wind turbine drivetrain on a nacelle test bench
Hongkun Zhang, Paula Weidinger, Christian Mester, Zihang Song, Marcel Heller, Alexander Dubowik, Bernd Tegtmeier, and Karin Eustorgi
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-70, https://doi.org/10.5194/wes-2024-70, 2024
Preprint under review for WES (discussion: final response, 2 comments)
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Drivetrain efficiency is a wind turbine’s fundamental behaviour in the energy conversion. To determine the efficiency, input and output powers need to be measured with sufficient accuracy. However, this is a very challenging task due to high complexity and lack of proper calibrated torque measurement. In cooperation with the German and Swiss national metrology institutes, the efficiency determination with state-of-the art instrumentations is demonstrated here with test processes and results.
25 Jul 2024
Semi-Analytical Methodology for Fretting Wear Evaluation of the Pitch Bearing Raceways Under Operative and Non-Operative Periods
David Cubillas, Mireia Olave, Iñigo Llavori, Ibai Ulacia, Jon Larrañaga, Aitor Zurutuza, and Arkaitz Lopez
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-78, https://doi.org/10.5194/wes-2024-78, 2024
Revised manuscript accepted for WES (discussion: closed, 7 comments)
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In this work, we propose a methodology for evaluating fretting in wind turbine pitch bearing raceways, complemented by a detailed case study. The methodology considers the coupled effects of radial fretting and rotational fretting. The method was previously validated at laboratory and now it is applied to large 4 point contact ball bearings and the 5MW NREL reference turbine. The evaluation reveals critical times for damage initiation and indicate alarmingly short times for fretting initiation.
24 Jul 2024
On the influence of cross-sectional deformations on the aerodynamic performance of wind turbine rotor blades
Julia Sabrina Gebauer, Felix Konstantin Prigge, Dominik Ahrens, Lars Wein, and Claudio Balzani
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-91, https://doi.org/10.5194/wes-2024-91, 2024
Revised manuscript accepted for WES (discussion: final response, 9 comments)
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The amount of energy that can be extracted from wind depends primarily on the blade geometry, which can be affected by elastic deformations. This paper presents a first study analysing the influence of cross-sectional deformations of a 15 MW wind turbine blade on the aero-elastic simulations. The results show small changes in geometry, and aerodynamic and structural loads even for a test case. These findings show the potential to be particularly important for larger and more flexible blades.
17 Jul 2024
Identification of operational deflection shapes of a wind turbine gearbox using fiber-optic strain sensors on a serial production end-of-line test bench
Unai Gutierrez Santiago, Aemilius van Vondelen, Alfredo Fernández Sisón, Henk Polinder, and Jan-Willem van Wingerden
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-83, https://doi.org/10.5194/wes-2024-83, 2024
Revised manuscript accepted for WES (discussion: closed, 4 comments)
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Knowing the loads applied to wind turbine gearboxes throughout their service life is becoming increasingly important. Operational deflection shapes identified from fiber-optic strain measurements have enabled the estimation of the gearbox input torque. This allows for future improvements in assessing the remaining useful life. Additionally, tracking the operational deflection shapes over time could enhance condition monitoring in planetary gear stages.
16 Jul 2024
A New Gridded Offshore Wind Profile Product for US Coasts Using Machine Learning and Satellite Observations
James Frech, Korak Saha, Paige D. Lavin, Huai-Min Zhang, James Reagan, and Brandon Fung
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-77, https://doi.org/10.5194/wes-2024-77, 2024
Revised manuscript under review for WES (discussion: final response, 6 comments)
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A machine learning model is developed using lidar stations around the US coasts to extrapolate wind speed profiles up to the hub heights of wind turbines from surface wind speeds. Independent validation shows that our model vastly outperforms traditional methods for vertical wind extrapolation. We produce a new long-term gridded dataset of wind speed profiles from 20 to 200 m at 0.25°, 6-hourly resolution from 1987 to 2022 by applying this model to the NOAA/NCEI Blended Seawinds product.
16 Jul 2024
Convergence and efficiency of global bases using proper orthogonal decomposition for capturing wind turbine wake aerodynamics
Juan Felipe Céspedes Moreno, Juan Pablo Murcia León, and Søren Juhl Andersen
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-81, https://doi.org/10.5194/wes-2024-81, 2024
Preprint under review for WES (discussion: final response, 3 comments)
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The use of a global base in a proper orthogonal decomposition provides a common base for analyzing flows, such as wind turbine wakes, across an entire parameter space. This can be used to compare flows with different conditions using the same physical interpretation. This work shows the convergence of the global base, its small error compared to the truncation error of 100 modes in the proper orthogonal decomposition, and the insensitivity to which datasets are included for generating it.
15 Jul 2024
Turbine- and farm-scale power losses in wind farms: an alternative to wake and farm blockage losses
Andrew Kirby, Takafumi Nishino, Luca Lanzilao, Thomas D. Dunstan, and Johan Meyers
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-79, https://doi.org/10.5194/wes-2024-79, 2024
Revised manuscript accepted for WES (discussion: closed, 4 comments)
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Traditionally, the aerodynamic loss of wind farm efficiency is classified into ‘wake loss’ and ‘farm blockage loss’. This study, using high-fidelity simulations, shows neither of these two losses is well correlated with the overall farm efficiency. We propose new measures called ’turbine-scale efficiency’ and ‘farm-scale efficiency’ to better describe turbine-wake effects and farm-atmosphere interactions. This study suggests the importance of better modelling ‘farm-scale loss’ in future studies.
04 Jul 2024
Linking weather patterns to observed and modelled turbine hub-height winds offshore U.S. West Coast
Ye Liu, Timothy W. Juliano, Raghavendra Krishnamurthy, Brian J. Gaudet, and Jungmin Lee
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-76, https://doi.org/10.5194/wes-2024-76, 2024
Revised manuscript accepted for WES (discussion: closed, 4 comments)
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Our study reveals how different weather patterns influence wind conditions off the U.S. West Coast. We identified key weather patterns affecting wind speeds at potential wind farm sites using advanced machine learning. This research helps improve weather prediction models, making wind energy production more reliable and efficient.
02 Jul 2024
Repair of wind turbine blades: Experience and observations from India – A Review
Refugine Nirmal Ignacy Muthu, Leon Mishnaevsky Jr., Saravanakumar Savadaiyan, Thamodharan Krishnaraj, Anthonyraj Premkumar S, Mohammed Farook S, and Kadhirvel Boopathi
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-55, https://doi.org/10.5194/wes-2024-55, 2024
Manuscript not accepted for further review (discussion: closed, 7 comments)
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This paper outlines wind turbine blade repair strategies in India, crucial for its expanding wind energy sector. It discusses challenges, repair techniques for various damages, and the importance of tailored maintenance. Practical cases and monitoring processes are explored, aiming to enhance the reliability of wind turbine blades in the region.
01 Jul 2024
Flow acceleration statistics: a new paradigm for wind-driven loads, towards probabilistic turbine design
Mark Kelly
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-69, https://doi.org/10.5194/wes-2024-69, 2024
Revised manuscript under review for WES (discussion: final response, 4 comments)
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Industrial standards for wind turbine design are based on 10-minute statistics of wind speed at turbine hub-height, treating fluctuations as turbulence. But recent work shows the effect of strong transients is described by flow accelerations. We devise a method to measure the accelerations turbines encounter; the extremes offshore defy 10-minute statistics, due to various phenomena beyond turbulence. These findings are translated into a recipe supporting statistical turbine design.
01 Jul 2024
Performance enhancements on wind turbines using flow controllers: A review
Kiarash Kord, Amir Noori, Nahid Hasanpour, Ali Heydari, Homayoun Askarpour, Mehdi Kashfi, and Shayan Pakravan
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-63, https://doi.org/10.5194/wes-2024-63, 2024
Revised manuscript has not been submitted (discussion: closed, 5 comments)
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Flow controllers hold promise for boosting wind turbine efficiency by smoothing airflow, optimizing blade angles, and reducing stress on blades. This review examines how different flow controller designs and wind speeds impact turbine performance, paving the way for future advancements in wind energy technology.
28 Jun 2024
Probabilistic lifetime extension assessment using mid-term data: Lillgrund wind farm case study
Shadan Mozafari, Jennifer Rinker, Paul Veers, and Katherine Dykes
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-68, https://doi.org/10.5194/wes-2024-68, 2024
Preprint under review for WES (discussion: final response, 7 comments)
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The study clarifies the use of probabilistic extrapolation of short/mid-term data for long-term site-specific fatigue assessments. In addition, it assesses the accountability of the Frandsen model in the Lillgrund wind farm as an example of compact layout.
12 Jun 2024
A Comprehensive Design Methodology of Shared Mooring Line Configurations for Assessing Mooring Costs and Performances of Floating Offshore Wind Turbines
Qi Pan, Dexing Liu, Feng Guo, and Po Wen Cheng
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-44, https://doi.org/10.5194/wes-2024-44, 2024
Revised manuscript under review for WES (discussion: final response, 3 comments)
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The floating wind market is striving to scale up from a handful of prototypes to gigawatt-scale capacity, despite facing barriers of high costs in the deep-sea deployment. Shared mooring is promising in reducing material costs. This paper introduces a comprehensive design methodology for reliable shared mooring line configurations, and reveals their potential for cost-saving and power enhancement. These findings contribute to achieving cost-effective solutions for floating wind farms.
10 Jun 2024
Dynamic Response of Offshore Wind Turbine Structure under Multi-load Coupling Based on DEM and FEM Joint Analysis
Xin Guan, Haoran Xu, Ying Yuan, Shuaijie Wang, Chenhao Zhao, and Hua Yu
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-66, https://doi.org/10.5194/wes-2024-66, 2024
Revised manuscript not accepted (discussion: closed, 6 comments)
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The structural dynamic characteristics of offshore wind turbines are directly related to the operational safety and equipment reliability of these turbines in service. Our findings indicate that under coupling effects from wind-wave-ice loads, lateral and longitudinal displacement at the tower top as well as lateral and longitudinal bending moment at the tower foundation are greater compared to individual loads.
10 Jun 2024
Annual wake impacts in and between wind farm clusters modelled by a mesoscale numerical weather prediction model and fast-running engineering models
Sara Porchetta, Michael F. Howland, Ruben Borgers, Sophia Buckingham, and Wim Munters
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-58, https://doi.org/10.5194/wes-2024-58, 2024
Preprint under review for WES (discussion: final response, 3 comments)
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This study delves into how hourly and monthly variations of wakes of a newly constructed wind farm cluster impacts adjacent existing farms. Using a simulation of a full year, it compares results from both a numerical weather prediction model and different fast-running engineering models. The results reveal significant differences in wake predictions, both quantitatively and qualitatively. Such insights are important for making informed decisions for the siting and design of future wind turbines.
03 Jun 2024
Offshore wind farms modify low-level jets
Daphne Quint, Julie K. Lundquist, and David Rosencrans
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-48, https://doi.org/10.5194/wes-2024-48, 2024
Revised manuscript accepted for WES (discussion: closed, 4 comments)
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Offshore wind farms will be built along the east coast of the United States. Low-level jets (LLJs) – layers of fast winds at low altitudes – also occur here. LLJs provide wind resources and also influence moisture and pollution transport, so it is important to understand how they might change. We develop and validate an automated tool to detect LLJs, and compare one year of simulations with and without wind farms. Here, we describe LLJ characteristics and how they change with wind farms.
31 May 2024
Turbine Repositioning Technique for Layout Economics (TRTLE) in Floating OffshoreWind Farms – Humboldt Case Study
Yuksel Rudy Alkarem, Kimberly Huguenard, Richard Kimball, Spencer Hallowell, Amrit Verma, Erin Bachynski-Polić, and Amir Nejad
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-67, https://doi.org/10.5194/wes-2024-67, 2024
Preprint under review for WES (discussion: final response, 7 comments)
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This research is a "less-is-more" demonstration of a novel concept that boost the efficiency of floating wind farms while maintaining fewer number of mooring line/anchors, reducing cost and the large footprint wind farms can have over the ocean bed and the water column. The novelty of this work lies in the passive wake steering method to enhance annual energy production and in integrating that with configurations that allow shared/multiline anchoring potential.
27 May 2024
Velocity correction for the Actuator Line Method
Davide Selvatici and Richard J. A. M. Stevens
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-60, https://doi.org/10.5194/wes-2024-60, 2024
Manuscript not accepted for further review (discussion: closed, 3 comments)
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The Actuator Line Method is to date one of the most adopted models for wind turbines in numerical simulations, yet it is known to overestimate the loading at the blade tips. We developed an extremely efficient correction methodology that is able to retrieve the loading distribution of Blade Element Method with tip correction independently on the turbine adopted, or on the chosen inflow velocity, making it possible to be used for simulations of wind farms.
24 May 2024
Estimating Long-Term Annual Energy Production of a Large Offshore Wind Farm from Large-Eddy Simulations: Methods and Validation with a 10-Year Simulation
Bernard Postema, Remco Verzijlbergh, Pim van Dorp, Peter Baas, and Harm Jonker
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-54, https://doi.org/10.5194/wes-2024-54, 2024
Preprint under review for WES (discussion: final response, 6 comments)
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Atmospheric large-eddy simulation is a technique that simulates weather conditions high detail, and is used to plan new wind farms. This research presents ways to estimate the long-term (10-year) power production of a wind farm, without having to simulate 10 years of weather, but much shorter (one year or less). The results show that the methods reduce the uncertainty in power production estimates by an order of magnitude, and that wind observations can be included as well to add more insight.
22 May 2024
Wind farm layout optimisation including meandering correction and momentum conserving superposition
Daniel Sukhman, Jan Bartl, Thomas H. Hansen, and Gloria Stenfelt
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-62, https://doi.org/10.5194/wes-2024-62, 2024
Preprint under review for WES (discussion: final response, 6 comments)
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This study introduces Qwyn, a tool for predicting wind flow and power output in large offshore wind farms. Combining advanced models and validated with data from Horns Rev 1, Qwyn accurately simulates various wind conditions. It enhances power predictions for both narrow and wide wind directions. Using Qwyn, a wind farm layout was optimized, leading to a projected 0.12 % increase in annual power production with a new convex row design.
17 May 2024
Periods of constant wind speed: How long do they last in the turbulent atmospheric boundary layer?
Daniela Moreno, Jan Friedrich, Matthias Wächter, Jörg Schwarte, and Joachim Peinke
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-32, https://doi.org/10.5194/wes-2024-32, 2024
Revised manuscript accepted for WES (discussion: closed, 8 comments)
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Considerably large and unexpected load events are measured on operating wind turbines, but they are not predicted by numerical simulations. As a possible explanation, we define, measure, and characterize the statistics of periods of constant wind speed. Additional comparisons to synthetic and pure turbulent data suggest that such events are not intrinsic to small-scale turbulence and are not accurately described by current standard models of the wind.
15 May 2024
Extension of the Langevin power curve analysis by separation per operational state
Christian Wiedemann, Hendrik Bette, Matthias Wächter, Jan A. Freund, Thomas Guhr, and Joachim Peinke
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-52, https://doi.org/10.5194/wes-2024-52, 2024
Revised manuscript under review for WES (discussion: final response, 3 comments)
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This study utilizes a method to analyze power conversion dynamics across different operational states, addressing non-stationarity with a correlation matrix algorithm. Findings reveal distinct dynamics for each state, emphasizing their impact on system behavior and offering a solution to hysteresis effects in power conversion dynamics.
08 May 2024
Numerical Analysis of Transonic Flow over the FFA-W3-211 Wind Turbine Tip Airfoil
Maria Cristina Vitulano, Delphine Anne Marie De Tavernier, Giuliano De Stefano, and Dominic Alexander von Terzi
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-47, https://doi.org/10.5194/wes-2024-47, 2024
Revised manuscript accepted for WES (discussion: closed, 3 comments)
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Next-generation wind turbines are the largest rotating machines ever built, experiencing local flow Mach where the incompressibility assumption is violated, and even transonic flow can occur. This study assesses the transonic features over the FFA-W3-211 wind turbine tip airfoil for selected industrial test cases, defines the subsonic-supersonic flow threshold, and evaluates the Reynolds number effects on transonic flow occurrence. Shock wave occurrence is also depicted.
07 May 2024
Meteorological Impacts of Offshore Wind Turbines as Simulated in the Weather Research and Forecasting Model
Daphne Quint, Julie K. Lundquist, Nicola Bodini, and David Rosencrans
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-53, https://doi.org/10.5194/wes-2024-53, 2024
Preprint under review for WES (discussion: final response, 7 comments)
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Offshore wind farms along the US east coast can have limited effects on local weather. Studying this, we used a weather model to compare conditions with and without wind farms near Massachusetts and Rhode Island. We analyzed changes in wind, temperature, and turbulence. Results show reduced wind speeds near and downwind of wind farms, especially during stability and high winds. Turbulence increases near wind farms, affecting boundary-layer height and wake size.
06 May 2024
Swell Impacts on an Offshore Wind Farm in Stable Boundary Layer: Wake Flow and Energy Budget Analysis
Xu Ning and Mostafa Bakhoday-Paskyabi
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-38, https://doi.org/10.5194/wes-2024-38, 2024
Revised manuscript under review for WES (discussion: final response, 3 comments)
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Waves interact with the overlying wind field by modifying the stresses at the atmosphere-ocean interface. We develop and employ a parameterization method of wave-induced stresses in the numerical simulation of an offshore wind farm in a stable atmospheric boundary layer. This work demonstrates how swells change the kinetic energy transport, and induce wind veer and wake deflection, leading to significant variations in the power output of wind turbines at different positions of the wind farm.
06 May 2024
Evaluating the potential of short-term instrument deployment to improve distributed wind resource assessment
Lindsay M. Sheridan, Dmitry Duplyakin, Caleb Phillips, Heidi Tinnesand, Raj K. Rai, Julia E. Flaherty, and Larry K. Berg
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-37, https://doi.org/10.5194/wes-2024-37, 2024
Revised manuscript under review for WES (discussion: final response, 4 comments)
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Twelve months of onsite wind measurement is standard for correcting model-based long-term wind speed estimates for utility-scale wind farms, however, the time and capital investment involved in gathering onsite measurements must be reconciled with the energy needs and funding opportunities for distributed wind projects. This study aims to answer the question of how low can you go in terms of the observational time period needed to make impactful improvements to long-term wind speed estimates.
02 May 2024
The multiple understandings of wind turbine noise: Reviewing scientific attempts at handling uncertainty
Julia K. Kirkegaard, Tom H. Cronin, Sophie Nyborg, and Daniel N. Frantzen
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-34, https://doi.org/10.5194/wes-2024-34, 2024
Revised manuscript accepted for WES (discussion: closed, 11 comments)
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Noise from wind turbines has been a point of contention for many years for those that have to live near wind farms. Despite strict regulations and significant research into the subject, it continues to be an issue for wind energy in the green transition. We were curious to try to find out why. Our research into three research (‘epistemic’) communities shows that noise is not understood as the same thing by the scientists dealing with it, fuelling the controversies over the solutions proposed.
29 Apr 2024
Dynamic Modelling and Response of a Power Cable connected to a Floating Wind Turbine
David Robert Verelst, Rasmus Sode Lund, and Jean-Philippe Roques
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-24, https://doi.org/10.5194/wes-2024-24, 2024
Publication in WES not foreseen (discussion: closed, 2 comments)
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This study discusses key issues when performing simulations of a dynamic power cable that is connected to a floating wind turbine. Such simulations are an important tool to asses if the floater and cable motions cause the power cable to survive or fail specific conditions, and generally assure they can fulfil their intended design life. This work describes how to model such power cables and combine that with a fully coupled model of an operating floating wind turbine.
29 Apr 2024
Full Scale Wind Turbine Performance Assessment: A Customised, Sensor-Augmented Aeroelastic Modelling Approach
Tahir H. Malik and Christian Bak
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-49, https://doi.org/10.5194/wes-2024-49, 2024
Revised manuscript accepted for WES (discussion: closed, 4 comments)
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This research integrates custom sensors into wind turbine simulation models for improved performance monitoring utilising a developed method. Real-world data validation demonstrates that enhanced sensor accuracy increases annual energy production and extends operational lifespan. This approach addresses the need for precise performance assessments in the evolving wind energy sector, ultimately promoting sustainability and efficiency.
26 Apr 2024
Analysis of a 30 GW offshore wind power scenario in Norway using time-series computed from numerical weather model data
Harald Georg Svendsen and John Olav Giæver Tande
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-45, https://doi.org/10.5194/wes-2024-45, 2024
Preprint withdrawn (discussion: closed, 4 comments)
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Norway is planning a doubling of its power generation capacity with 30 GW of offshore wind over the next 25 years. To integrate this variable energy resource in the power system requires a good understanding of its characteristics. This paper demonstrates that wind power in the north is uncorrelated with wind in the south, that there is a large smoothing effect on power output, but nevertheless periods of low total wind power output for several days.
12 Apr 2024
Effect of Blade Inclination Angle for Straight Bladed Vertical Axis Wind Turbines
Laurence Boyd Morgan, Abbas Kazemi Amiri, William Leithead, and James Carroll
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-42, https://doi.org/10.5194/wes-2024-42, 2024
Revised manuscript accepted for WES (discussion: closed, 3 comments)
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This paper presents a systematic study into the effect of blade inclination angle, chord distribution, and blade length on vertical axis wind turbine performance. It is shown that for rotors of identical power production, both blade volume and rotor torque can be significantly reduced through the use of aerodynamically optimised inclined rotor blades. This demonstrates the potential of V-Rotors to reduce the cost of energy for offshore wind when compared to H-Rotors.
05 Apr 2024
Observations of wind farm wake recovery at an operating wind farm
Raghavendra Krishnamurthy, Rob Newsom, Colleen Kaul, Stefano Letizia, Mikhail Pekour, Nicholas Hamilton, Duli Chand, Donna M. Flynn, Nicola Bodini, and Patrick Moriarty
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-29, https://doi.org/10.5194/wes-2024-29, 2024
Revised manuscript accepted for WES (discussion: closed, 4 comments)
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The growth of wind farms in the central United States in the last decade has been staggering. This study looked at how wind farms affect the recovery of wind wakes – the disturbed air behind wind turbines. In places like the US Great Plains, phenomena such as low-level jets can form, changing how wind farms work. We studied how wind wakes recover under different weather conditions using real-world data, which is important for making wind energy more efficient and reliable.
04 Apr 2024
Challenges in Detecting Wind Turbine Power Loss: The Effects of Blade Erosion, Turbulence and Time Averaging
Tahir H. Malik and Christian Bak
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-35, https://doi.org/10.5194/wes-2024-35, 2024
Revised manuscript accepted for WES (discussion: closed, 7 comments)
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This study investigates how wind turbine blades damaged by erosion, along with changing wind conditions, affect power output. Even minor blade damage can lead to significant energy losses, especially in turbulent winds. Using simulations, we discovered that standard power data analysis methods, including time-averaging, can hide these losses. This research highlights the need for better blade damage detection and careful wind data analysis to optimize wind farm performance.
02 Apr 2024
Characterization of Dynamic Stall on Large Wind Turbines
Hye Rim Kim, Jasson A. Printezis, Jan Dominik Ahrens, Joerg R. Seume, and Lars Wein
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-31, https://doi.org/10.5194/wes-2024-31, 2024
Revised manuscript accepted for WES (discussion: closed, 4 comments)
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The need of renewable energy, so thus more efficient wind turbines, is ever increasing. Accurate prediction of the performance in the design stage is a necessary. Especially, predicting the dynamic performance of wind turbine in the region where it undergoes highly unsteady flow, is very challenging. We investigated this dynamic performance of an airfoil, which is typical for the mega-structure wind farms, to support the development of more efficient design tools in the future.
02 Apr 2024
Probabilistic cost modeling as a basis for optimizing the inspection and maintenance of support structures in offshore wind farms
Muhammad Farhan, Ronald Schneider, Sebastian Thöns, and Max Gündel
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2023-176, https://doi.org/10.5194/wes-2023-176, 2024
Revised manuscript accepted for WES (discussion: closed, 4 comments)
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This paper formulates and applies a probabilistic cost model to support the operational management of offshore wind farms. It provides the decision-theoretical basis for the optimization of I&M regimes with an emphasis on integrating the probabilistic cost model into the decision analysis. The proposed probabilistic cost model is then applied in a numerical example and a value of information analysis is performed to quantify the cost effectiveness of the identified optimal I&M strategy.
27 Mar 2024
Drop-size-dependent effects in leading-edge rain erosion and their impact for erosion-safe mode operation
Nils Barfknecht and Dominic von Terzi
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-33, https://doi.org/10.5194/wes-2024-33, 2024
Revised manuscript accepted for WES (discussion: closed, 5 comments)
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The paper investigates the influence of the rain drop diameter on the formation of erosion damage and its implication for the erosion-safe mode (ESM). By building an erosion damage model that incorporates several drop-size effects, it is found that large droplets are significantly more erosive than small droplets. It is shown that the performance of the ESM is significantly increased when drop-size effects are correctly accounted for. A method to derive optimal ESM strategies is given as well.
20 Mar 2024
On the Uncertainty of Digital Twin Models for Load Monitoring and Fatigue Assessment in Wind Turbine Drivetrains
Felix Christian Mehlan and Amir R. Nejad
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-28, https://doi.org/10.5194/wes-2024-28, 2024
Revised manuscript accepted for WES (discussion: closed, 3 comments)
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A Digital Twin is a virtual representation that mirrors the wind turbine's real behavior through simulation models and sensor measurements and can assist in making key decisions such as planning the replacement of parts. These models and measurements are, of course, not perfect and only give an incomplete picture of the real behavior. This study investigates how large the uncertainty of such models and measurements is and to what extent it affects the decision-making process.
07 Mar 2024
Improving Wind and Power Predictions via Four-Dimensional Data Assimilation in the WRF Model: Case Study of Storms in February 2022 at Belgian Offshore Wind Farms
Tsvetelina Ivanova, Sara Porchetta, Sophia Buckingham, Jeroen van Beeck, and Wim Munters
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2023-177, https://doi.org/10.5194/wes-2023-177, 2024
Revised manuscript accepted for WES (discussion: closed, 3 comments)
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This study explores how wind and power predictions can be improved by introducing local forcing of measurement data in a numerical weather model, while taking into account the presence of neighboring wind farms. Practical implications for the wind energy industry include insights for informed offshore wind farm planning and decision-making strategies using open-source models, even under adverse weather conditions.
27 Feb 2024
The Effects of Wind Farm Wakes on Freezing Sea Spray in the Mid-Atlantic Offshore Wind Energy Areas
David Rosencrans, Julie K. Lundquist, Mike Optis, and Nicola Bodini
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-2, https://doi.org/10.5194/wes-2024-2, 2024
Revised manuscript accepted for WES (discussion: closed, 4 comments)
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The U.S. offshore wind industry is growing rapidly. Expansion into cold climates will subject turbines and personnel to hazardous freezing. We analyze the 20-year freezing risk for US East Coast wind areas based on numerical weather prediction simulations and further assess impacts from wind farm wakes over one winter season. Sea-spray icing at 10 m can occur up to 66 hours per month. However, turbine–atmosphere interactions reduce icing hours within wind plant areas.
14 Feb 2024
Structural Design Optimization of Laminated Composites for Vertical Axis Wind Turbine Blades: A Single Objective Approach
Ahmed Ali Geneid, Mostofa R. Atia, Adel Elsabbagh, and Mohammed Hedaya
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-1, https://doi.org/10.5194/wes-2024-1, 2024
Revised manuscript under review for WES (discussion: final response, 5 comments)
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The paper presents an integrated model to be used in the design of a vertical-axis wind turbine blade to include the four critical design parameters, which are mass, cost, life, and fundamental frequency. The model is embedded in an optimization approach. The inclusion of fatigue and blade life assessments has a great impact on optimum results. The approach has low computational time and is capable of generating new materials with a higher sustainability index (100 % eco-friendly).
14 Feb 2024
Some comments on experimental results of three lift controllers for a wind turbine blade section using an active flow control
Loïc Michel, Caroline Braud, Jean-Pierre Barbot, Franck Plestan, Dimitri Peaucelle, and Xavier Boucher
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-15, https://doi.org/10.5194/wes-2024-15, 2024
Revised manuscript accepted for WES (discussion: closed, 3 comments)
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Capturing energy from a wind turbine requires control algorithms to manage in real-time the operation of the wind turbine in order to optimize the energy extraction. This work focuses on the development of control algorithms applied at the level of the blade section to interact locally with the aerodynamics flow and hence modify the aerodynamic lift. Some dedicated control strategies are experimentally investigated to give an overview of performances according to different operating scenarios.
13 Feb 2024
Data assimilation of realistic boundary-layer flows for wind-turbine applications – An LES study
Linus Wrba, Antonia Englberger, Andreas Dörnbrack, Gerard Kilroy, and Norman Wildmann
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-12, https://doi.org/10.5194/wes-2024-12, 2024
Revised manuscript under review for WES (discussion: final response, 4 comments)
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It is crucial to understand the loads and power production of wind turbines under different atmospheric situations (e.g. night and day changes). Computational simulations are a widely used tool to get more knowledge of the performance and the wake of wind turbines. In this study realistic velocity profiles of the atmosphere are used as input for simulations so that these simulations become more realistic. The generated realistic flow is used as inflow for wind-turbine simulations.
12 Feb 2024
Anomalous Response of Floating Offshore Wind Turbine to Wind and Waves
Yihan Liu and Michael Chertkov
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-14, https://doi.org/10.5194/wes-2024-14, 2024
Revised manuscript not accepted (discussion: closed, 5 comments)
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This study offers new insights into anomalous dynamics of Floating Offshore Wind Turbines under varying wind and waves, using Monte Carlo simulations. Key findings reveal that while waves may play a role, wind largely dictates long-term anomalies, crucial for future FOWT design and control.
05 Feb 2024
Characterization of Local Wind Profiles: A Random Forest Approach for Enhanced Wind Profile Extrapolation
Farkhondeh Rouholahnejad and Julia Gottschall
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2023-178, https://doi.org/10.5194/wes-2023-178, 2024
Revised manuscript accepted for WES (discussion: closed, 3 comments)
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In wind energy, precise wind speed prediction at hub-height is vital. Our study in the Dutch North Sea reveals that the on-site trained random forest model outperforms the global reanalysis data, ERA5, in accuracy and precision. Trained within a 200 km range, the model effectively extends the wind speed vertically but experiences bias. It also outperforms corrected ERA5 in capturing wind speed variations and fine wind patterns, highlighting its potential for offshore wind resource assessment.
30 Jan 2024
Load case selection for finite element simulations of wind turbine pitch bearings and hubs
Matthias Stammler and Florian Schleich
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2023-163, https://doi.org/10.5194/wes-2023-163, 2024
Revised manuscript under review for WES (discussion: final response, 9 comments)
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The structures at the center of wind turbine rotors are loaded by the three rotor blades. The rotor blades have different loads which depend on their positions and the incoming wind. The number of possible different loads is too high to simulate each of them for later design of the structures. This work attempts to reduce the number of necessary simulations by exploring inherent relations between the loads of the three rotor blades.
29 Jan 2024
Reconstruction and Evaluation of a Single-scanning LiDAR-based wind Field Measurements using LES
Masakage Taguchi, Jay Prakash Goit, and Takatsugu Kameda
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-8, https://doi.org/10.5194/wes-2024-8, 2024
Manuscript not accepted for further review (discussion: closed, 3 comments)
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The current work models a single scanning LiDAR-based wind field measurements in the large-eddy simulations (LES) of the atmospheric boundary layer flow. The aim is to evaluate the effect of scan parameters on the accuracy of two-parameter VVP method which is used extensively to retrieve velocity vector from LiDAR-measured radial wind speed. It was found that mean wind speed can be computed accurately from a single LiDAR data, though turbulence intensities are mostly underestimated.
23 Jan 2024
Load assessment of a wind farm considering negative and positive yaw misalignment for wake steering
Regis Thedin, Garrett Barter, Jason Jonkman, Rafael Mudafort, Christopher J. Bay, Kelsey Shaler, and Jasper Kreeft
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-6, https://doi.org/10.5194/wes-2024-6, 2024
Revised manuscript accepted for WES (discussion: closed, 4 comments)
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This work investigates asymmetries in terms of power performance and fatigue loading on a 5-turbine wind farm subject to wake steering strategies. Both the yaw misalignment angle and the wind direction were varied from negative to positive. We highlight conditions in which fatigue loading is lower while still maintenance good power gains and show that partial wake is the source of the asymmetries observed. We provide recommendations in terms of yaw misalignment angles for a given wind direction.
17 Jan 2024
Grand Challenges in Social Aspects of Wind Energy Development
Lena Kitzing, David Rudolph, Sophie Nyborg, Helena Solman, Tom Cronin, Gundula Hübner, Elizabeth Gill, Katherine Dykes, Suzanne Tegen, and Julia Kirch Kirkegaard
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2023-174, https://doi.org/10.5194/wes-2023-174, 2024
Preprint withdrawn (discussion: closed, 6 comments)
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Social aspects are gaining traction in wind energy. A recent publication by Kirkegaard et al. lays out social grand challenges. We discuss them for a more technologically focused audience. We describe the role of social sciences in wind energy research, showing insights, topics, and value-added for public engagement and planning, just ownership and value-based design. We reflect how social and technical sciences can jointly advance wind energy research into a new interdisciplinary era.
16 Jan 2024
Optimal allocation of 30GW offshore wind power in the Norwegian Economic Zone
Sondre Hølleland, Geir Drage Berentsen, Håkon Otneim, and Ida Marie Solbrekke
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-5, https://doi.org/10.5194/wes-2024-5, 2024
Revised manuscript accepted for WES (discussion: closed, 4 comments)
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The paper applies portfolio selection methodology to the problem of allocating offshore wind farm resources to various potential wind farm regions in Norway. The allocation aims to achieve high and stable wind power production under various constraints. Spreading the wind farms geographically has a large impact on the stability of the portfolio in terms of variance, and the results are consistent for the two sets of candidate regions studied. Sequential selection gives a good solution.
15 Jan 2024
Non-proportionality analysis of multiaxial fatigue stress histories in trailing edge adhesive joints of wind turbine rotor blades
Claudio Balzani and Pablo Noever Castelos
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2023-167, https://doi.org/10.5194/wes-2023-167, 2024
Revised manuscript under review for WES (discussion: final response, 5 comments)
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Wind turbine rotor blades consist of several subcomponents that are glued together. Such connections are subjected to fatigue loads. This paper analyzes the characteristics of those fatigue loads in trailing edge adhesive joints of three different wind turbine rotor blades. It is shown that the fatigue loads have significant degrees of non-proportionality, which helps engineers to choose a valid fatigue analysis framework and to design more reliable and cost-efficient rotor blades in the future.
11 Jan 2024
Analysis of Turbine Yaw Misalignment Estimated by LIDAR Assuming Homogeneous Flow
Zhaoyu Zhang, Feng Guo, David Schlipf, Paolo Schito, and Alberto Zasso
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2023-162, https://doi.org/10.5194/wes-2023-162, 2024
Preprint withdrawn (discussion: closed, 2 comments)
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This paper aims to analyse the uncertainty in wind direction estimation of LIDAR and to improve the estimation accuracy. Findings demonstrate that this LIDAR estimation method is insufficient to supervise the turbine yaw control system in terms of both accuracy and timeliness. Future research should apply more advanced wind flow models to explore more accurate wind field reconstruction methods.
09 Jan 2024
On predicting offshore hub-height wind speed and wind power density in the Northeast US coast using high-resolution WRF model configurations during anticyclones coinciding with wind drought
Tasnim Zaman, Timothy Juliano, Pat Hawbecker, and Marina Astitha
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2023-148, https://doi.org/10.5194/wes-2023-148, 2024
Preprint withdrawn (discussion: closed, 2 comments)
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We suggest a model configuration to predict offshore wind speed and wind power density in the Northeast US. We focused on wind droughts, long periods of low wind speed that affect the reliability of wind power generation. We show that wind prediction depends primarily on the initial and boundary conditions, and that it is important to evaluate the connection of wind speed to wind power generation, to select the best model configuration.
11 Dec 2023
Modeling unsteady loads on wind-turbine blade sections from periodic structural oscillations and impinging gusts
Nathaniel James Wei and Omkar Bhalchandra Shende
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2023-164, https://doi.org/10.5194/wes-2023-164, 2023
Manuscript not accepted for further review (discussion: closed, 8 comments)
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Many methods for wind turbine design treat incoming gusts and blade deflections as changing slowly enough to be approximated as constant. This is not true in reality, but we can build a model for these effects from functions that can solve similar problems for aircraft wings. We run numerical simulations to validate this model using sections of a blade and find it predicts lift forces well. This method can help turbine analysis tools increase the robustness and performance of turbine blades.
08 Dec 2023
Validation of a traceable efficiency determination method for wind turbines with a focus on measurement uncertainty
Nijan Yogal, Christian Lehrmann, Paula Weidinger, Zihang Song, Hongkun Zhang, Maximilian Zweiffel, and Christian Mester
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2023-165, https://doi.org/10.5194/wes-2023-165, 2023
Revised manuscript not accepted (discussion: closed, 4 comments)
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This paper examines global initiatives for energy-efficient wind turbines, exploring new approaches based on international standards. The conclusion underlines the urgency of transitioning to clean energy, highlighting the iso-efficiency map's potential for validating total efficiency. Encouraging standardized testing, research addresses challenges in testing energy-efficient machines, emphasizing precise measurements.
21 Nov 2023
Predicting the Onset of Dynamic Stall on Large Wind Turbines
Jan Dominik Ahrens, Jasson A. Printezis, Ahmed G. Yosry, Joerg R. Seume, and Lars Wein
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2023-159, https://doi.org/10.5194/wes-2023-159, 2023
Manuscript not accepted for further review (discussion: closed, 3 comments)
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Dynamic stall introduces transient loads that excite blade vibrations, which contribute to mechanical fatigue and can lead to blade failure. In order to design wind turbine airfoils that are less prone to dynamic stall, the onset of dynamic stall has to be predicted. This work contributes to the development of reduced-order models that predict dynamic stall in a cost-efficient way. The models can be used in the design process of new airfoil geometries of future wind turbines.
02 Nov 2023
Dynamic displacement measurement of a wind turbine tower using accelerometers: tilt error compensation and validation
Clemens Jonscher, Paula Helming, David Märtins, Andreas Fischer, David Bonilla, Benedikt Hofmeister, Tanja Grießmann, and Raimund Rolfes
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2023-123, https://doi.org/10.5194/wes-2023-123, 2023
Revised manuscript accepted for WES (discussion: closed, 4 comments)
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This study investigates dynamic displacement estimation using double time integrated acceleration signals for future application in load monitoring based on accelerometers. To estimate displacements without amplitude distortion, a tilt error compensation method for low frequency vibrations of tower structures using the static bending line without the need for additional sensors is presented. The method is validated using a full-scale onshore wind turbine tower and a terrestrial laser scanner.
20 Oct 2023
Measurement and analysis of high altitude wind profiles over the sea in a coastal zone using a scanning wind LiDAR – application to wind energy
Boris Conan and Aleksandra Visich
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2023-141, https://doi.org/10.5194/wes-2023-141, 2023
Revised manuscript not accepted (discussion: closed, 3 comments)
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The paper describes an original field experiment using a scanning LiDAR set up to measure the wind profile above the sea surface up to an altitude of 500 m. Reaching this height with a good vertical resolution is key for the wind energy sector, especially for wind turbine design, load and fatigue predictions. Observations at the site include low-level jets and extreme wind shear that are observed 15 % and 30 % of the time, respectively.
16 Oct 2023
The winds are twisting: analysis of strong directional shear across the rotor plane using coastal lidar measurements and ERA5
Christoffer Hallgren, Heiner Körnich, Stefan Ivanell, Ville Vakkari, and Erik Sahlée
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2023-129, https://doi.org/10.5194/wes-2023-129, 2023
Preprint withdrawn (discussion: closed, 5 comments)
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Sometimes, the wind changes direction between the bottom and top part of a wind turbine. This affects both the power production and the loads on the turbine. In this study, a climatology of pronounced changes in wind direction across the rotor is created, focusing on Scandinavia. The weather conditions responsible for these changes in wind direction are investigated and the climatology is compared to measurements from two coastal sites, indicating an underestimation by the climatology.
27 Sep 2023
Implementation of a Near-Wake Region within the Curled-Wake Model
Paul Hulsman, Luis A. Martínez-Tossas, Nicholas Hamilton, and Martin Kühn
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2023-112, https://doi.org/10.5194/wes-2023-112, 2023
Manuscript not accepted for further review (discussion: closed, 2 comments)
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This paper presents an approach to analytically estimate the wake deficit within the near-wake region by modifying the curled wake model. This is done by incorporating a new initial condition at the rotor using an azimuth-dependent Gaussian profile, an adjusted turbulence model in the near-wake region and the far-wake region and an iterative process to determine the velocity field, while considering the relation of the pressure gradient and accounting the conservation of mass.
27 Sep 2023
Experimental evaluation of the motion-induced effects on turbulent fluctuations measurement on floating lidar systems
Nicolas Thebault, Maxime Thiébaut, Marc Le Boulluec, Guillaume Damblans, Christophe Maisondieu, Cristina Benzo, and Florent Guinot
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2023-126, https://doi.org/10.5194/wes-2023-126, 2023
Preprint withdrawn (discussion: closed, 4 comments)
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This study examines motion's impact on LOS turbulent velocity fluctuations measured by lidar profilers. Onshore tests used a mobile lidar (WindCube v2.1) on a hexapod, comparing it to a fixed lidar. RMSE was calculated to assess motion effects on turbulence. Results showed alignment, wind speed and amplitude as significant influences on RMSE. Motion frequency affected LOS velocity spectra but had limited impact on RMSE compared to other factors.
11 Sep 2023
Preliminary Techno-Economic Study of Optimized Floating Offshore Wind Turbine Substructure
Adebayo Ojo, Maurizio Collu, and Andrea Coraddu
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2023-96, https://doi.org/10.5194/wes-2023-96, 2023
Revised manuscript not accepted (discussion: closed, 5 comments)
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This is a nouvelle work conducted to aid the expedition of the Floating Offshore Wind Turbine (FOWT) technology to be as commercially viable as the fixed bottom foundation counterpart. This work is focused on the shape alteration of the FOWT platform within an optimization framework to reduce the cost of material for manufacturing the platforms; therefore, reducing the levelized cost of energy. This study also shows economics of scale further reduces the LCOE when the farm's size is increased.
30 Aug 2023
Industry 4.0 Digital Twins in Offshore Wind Farms
Evi Elisa Ambarita, Anniken Karlsen, Francesco Scibilia, and Agus Hasan
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2023-108, https://doi.org/10.5194/wes-2023-108, 2023
Revised manuscript not accepted (discussion: closed, 4 comments)
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Our study investigated the potential for knowledge transfer of industrial digital twins from the advanced manufacturing industry to offshore wind farms context, in alignment with Industry 4.0 standards. We conducted a literature review in both sectors and followed it up with a case study on offshore wind farms. Our findings provide valuable insight for the improvement of digital twins in offshore wind farms to perform interoperability, based on Industry 4.0 standards.
23 Aug 2023
Segmented Gurney Flaps for Enhanced Wind Turbine Wake Recovery
Nirav Dangi, Koen Boorsma, Edwin Bot, Wim Bierbooms, and Wei Yu
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2023-90, https://doi.org/10.5194/wes-2023-90, 2023
Preprint withdrawn (discussion: closed, 4 comments)
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The wind turbine wake is a downstream region of velocity deficit, resulting in a power loss for downstream wind turbines. A turbulator is proposed to minimize this velocity deficit. In this work, a very successful field test campaign was executed which demonstrated the use of segmented Gurney Flaps as a promising add-on to promote enhanced wind turbine wake recovery for improved overall wind farm farm performance.
16 Aug 2023
Fractal-based numerical simulation of multivariate typhoon wind speeds utilizing Weierstrass Mandelbrot function
Kang Cai, Mingfeng Huang, Qiang Li, Qing Wang, Yong Chen, and Lizhong Wang
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2023-91, https://doi.org/10.5194/wes-2023-91, 2023
Revised manuscript not accepted (discussion: closed, 6 comments)
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This paper firstly focuses on determining an appropriate method to estimate the fractal dimensions of fluctuating wind speed series. Then a new fractal-based multivariate simulation method was developed to capture the inherent fractal property and the nonstationary characteristic of typhoon wind speeds, both of which are ignored in the existing simulation methods. Field measurement data of a historical super typhoon was used to demonstrate the accuracy and effectiveness of the proposed methods.
14 Aug 2023
A Survey on Applications of Small Uncrewed Aircraft Systems for Offshore Wind Farms
Robert Sasse, C. Alexander Hirst, Eric Frew, and Brian Argrow
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2023-87, https://doi.org/10.5194/wes-2023-87, 2023
Preprint withdrawn (discussion: closed, 3 comments)
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Small uncrewed aircraft systems (sUAS) are becoming ubiquitous in a variety of fields including search and rescue, infrastructure inspection, large scale surveying, and atmospheric science. We believe there is potential for sUAS to support offshore windfarm projects. To this end we present this survey on academic literature which deploys sUAS in a variety of missions related to offshore wind farms: wind resource assessment, operational observation, infrastructure inspection.
31 Jul 2023
Gaussian wake model fitting in a transient event over Alpha Ventus wind farm
Maria Krutova and Mostafa Bakhoday-Paskyabi
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2023-79, https://doi.org/10.5194/wes-2023-79, 2023
Revised manuscript not accepted (discussion: closed, 4 comments)
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Wind turbine wake studies often rely on engineering models, which consist of simple analytical expressions. We review an atmospheric event resulting in a strong wind flow change within tens of minutes and apply several wake models to see how they respond to new conditions. We find that two models are consistent with their predictions, and one of them, the super-Gaussian model, predicts the wake shape particularly well; more attention should be paid to its development and implementation.
13 Jun 2023
Forecasting of wind power by using a hybrid machine learning method for the Nord-Pool intraday electricity market
Atilla Altintas, Lars Davidson, and Ola Carlson
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2023-48, https://doi.org/10.5194/wes-2023-48, 2023
Preprint withdrawn (discussion: closed, 3 comments)
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This study improves wind power forecasting accuracy with machine learning. A hybrid approach of Empirical Mode Decomposition (EMD) and Support Vector Regression (SVR), with a hyperparameter tuning, leads to higher accuracy. The wind turbine power data used and found that EMD-based approach is better than SVR. Applying parameter tuning showed significant improvement in wind power forecasting. The study's findings are important for energy traders looking to maximize profits in the intraday market.
07 Jun 2023
Brief communication: Betz’s Law: the Zorich Derivation
Richard Zorich
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2023-55, https://doi.org/10.5194/wes-2023-55, 2023
Preprint withdrawn (discussion: closed, 7 comments)
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Betz’s law states that the maximum efficiency of a wind-powered machine is 59 %. Betz disregards viscosity in order to use Bernoulli’s principle in his derivation. Assuming inviscid flow leads to a useful model. In contrast with Betz’s approach, my derivation, recognizes the key role that viscosity plays in the interaction of a wind-powered machine with the atmosphere. It is my belief that my model gives us better understanding of how a machine captures energy from the wind.
09 May 2023
Wind speed time series synthesis using a parametrized power spectral density function
Ram C. Poudel, David Corbus, and Ian Baring-Gould
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2023-45, https://doi.org/10.5194/wes-2023-45, 2023
Revised manuscript not accepted (discussion: closed, 4 comments)
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We propose a new method to synthesize 1 Hz wind speed and wind power time series data from the industry standard 10-minute wind turbine performance data. The method is based on a parameterized power spectral density (PSD) function decomposed into trend and random components. We illustrate the intra-timestep data synthesis utilizing 1 Hz data from two distributed wind turbines.
21 Apr 2023
Numerical Prediction of the Aerodynamics and Aeroacoustics of a Horizontal Axis Wind Turbine
Wen-Yu Wang and Yuh-Ming Ferng
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2023-32, https://doi.org/10.5194/wes-2023-32, 2023
Revised manuscript not accepted (discussion: closed, 4 comments)
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ANSYS FLUENT was used to simulate and compute the aerodynamic flow characteristics in different turbulence models in this study. The aerodynamic simulation results were validated using experimental measurements of the NREL Phase VI wind turbine. The V2f and SST k-ω turbulence models were used in this study. The prediction results of the separation flow, wake vortex, overall flow field, and sound field characteristics were similar to the results of the LES model and the experimental data.
21 Feb 2023
Aeroelastic Tailoring of Wind Turbine Rotors Using High-Fidelity Multidisciplinary Design Optimization
Marco Mangano, Sicheng He, Yingqian Liao, Denis-Gabriel Caprace, Andrew Ning, and Joaquim R. R. A. Martins
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2023-10, https://doi.org/10.5194/wes-2023-10, 2023
Revised manuscript not accepted (discussion: closed, 6 comments)
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High-fidelity MDO enables more effective system design than conventional approaches. MDO can shorten the wind turbine design cycle and reduce the cost of energy. We present a first-of-its-kind high-fidelity aerostructural optimization study of a turbine rotor using a coupled CFD-CSM solver. We simultaneously improve the rotor aerodynamic efficiency and reduce the mass of a rotor of a 10 MW wind turbine using 100+ design variables. We discuss the results with unprecedented detail.
17 Feb 2023
Potential of Dynamic Wind Farm Control by Axial Induction in the Case of Wind Gusts
Florian Bürgel, Robert Scholz, Christian Kirches, and Sebastian Stiller
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2023-2, https://doi.org/10.5194/wes-2023-2, 2023
Revised manuscript not accepted (discussion: closed, 3 comments)
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Wind turbines are an important electric power source. Usually, they are organized in wind farms. Thereby, each wind turbine causes a so-called wake with a reduced wind speed. This can influence following wind turbines and is an opportunity to optimize the operation of each wind turbine. A wind gust usually makes the tower oscillate. We control a wind turbine in a way such that the following turbine significantly less oscillates. Thereby, we also paid attention to the power of the wind turbines.
09 Feb 2023
Aerodynamic simulation of rough and eroded blades, AEP effect and mitigation using low drag vortex generators
David Bretos-Arguiñena and Beatriz Méndez-López
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2023-8, https://doi.org/10.5194/wes-2023-8, 2023
Revised manuscript not accepted (discussion: closed, 6 comments)
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Wind energy is crucial for dealing with the climatic change challenge. Society needs more efficient wind turbines reducing the costs and the operation and maintenance works. In addition, uncertainties should be also reduced. One of the biggest uncertainties in the wind energy field, is the wind turbine performance with regard to the blade status. Blades are living components and their surface changes with the wind turbine life evolution: they become dirty and or they suffer from erosion.
31 Jan 2023
The Impact of Climate Change on Extreme Winds over Northern Europe According to CMIP6
Xiaoli Guo Larsén, Marc Imberger, Ásta Hannesdóttir, and Andrea N. Hahmann
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2022-102, https://doi.org/10.5194/wes-2022-102, 2023
Revised manuscript not accepted (discussion: closed, 4 comments)
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We study how climate change will impact extreme winds and choice of turbine class. We use data from 18 CMIP6 members from a historic and a future period to access the change in the extreme winds. The analysis shows an overall increase in the extreme winds in the North Sea and the southern Baltic Sea, but a decrease over the Scandinavian Peninsula and most of the Baltic Sea. The analysis is inconclusive to whether higher or lower classes of turbines will be installed in the future.
27 Jan 2023
Regression-based Main Bearing Load Estimation
Amin Loriemi, Georg Jacobs, Vitali Züch, Timm Jakobs, and Dennis Bosse
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2022-75, https://doi.org/10.5194/wes-2022-75, 2023
Preprint withdrawn (discussion: closed, 2 comments)
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In the last decades, the size of wind turbines has continuously increased. The increasing rotor diameter results in higher loads acting on the main bearings of wind turbines. In this study, it is discussed how these loads can be estimated using accessible sensor signals and regression models. Therefore, measurement data has been acquired on a full-scale wind turbine test bench. It is shown that linear regression using displacement signals provides good accuracy in estimating main bearing loads.
09 Jan 2023
Comparison Metrics Microscale Simulation Challenge for Wind Resource Assessment
Florian Hammer, Sarah Barber, Sebastian Remmler, Federico Bernardoni, Kartik Venkatraman, Gustavo A. Díez Sánchez, Alain Schubiger, Trond-Ola Hågbo, Sophia Buckingham, and Knut Erik Giljarhus
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2022-114, https://doi.org/10.5194/wes-2022-114, 2023
Preprint withdrawn (discussion: closed, 4 comments)
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We further enhanced a knowledge base for choosing the most optimal wind resource assessment tool. For this, we compared different simulation tools for the Perdigão site in Portugal, in terms of accuracy and costs. In total five different simulation tools were compared. We found that with a high degree of automatisation and a high experience level of the modeller a cost effective and accurate prediction based on RANS could be achieved. LES simulations are still mainly reserved for academia.
10 Oct 2022
Aeroelastic Validation of the Offshore Wind Energy Simulator for Vertical-Axis Wind Turbines
Kevin Ray Moore and Brandon Lee Ennis
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2022-91, https://doi.org/10.5194/wes-2022-91, 2022
Revised manuscript not accepted (discussion: closed, 4 comments)
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This verification and validation effort summarizes the aeroelastic prediction capability of the Offshore Wind ENergy Simulator (OWENS). Cases ranging from simple analytical beams to an experimental vertical-axis turbine are compared and analyzed for modal, steady, and two-way aeroelastically-coupled dynamic operation with turbulent inflow. OWENS has demonstrated accuracy in both mean and varying loads for accurate design and certification of vertical-axis wind turbines.
10 Oct 2022
Population Based Structural Health Monitoring: Homogeneous Offshore Wind Model Development
Innes Murdo Black, Moritz Werther Häckell, and Athanasios Kolios
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2022-93, https://doi.org/10.5194/wes-2022-93, 2022
Revised manuscript accepted for WES (discussion: closed, 7 comments)
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Population based structural health monitoring is a low-cost monitoring campaign. The cost reduction from this type of digital enabled asset management tool is manifested by sharing information, in this case a wind farm foundation, within the population. By sharing the information in the wind farm this reduces the amount of sensors and physical model updating, reducing the cost of the monitoring campaign.
05 Sep 2022
Investigating Horizontal Axis Wind Turbine Aerodynamics Using Cascade Flows
Narges Golmirzaee and David H. Wood
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2022-76, https://doi.org/10.5194/wes-2022-76, 2022
Preprint withdrawn (discussion: closed, 1 comment)
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This study shows the importance of wind turbine blades' wake vorticity, which is ignored in blade-element momentum analysis. We derive a relation between the wake vorticity and blade element drag and demonstrate that the circulation in the wake of a blade element is partly determined by its drag. Also, we find that the airfoil assumption, which is that the elements behave as airfoils, is conservative; the lift:drag ratio of cascade elements is greater than that of the corresponding airfoils.
01 Sep 2022
A Surrogate Based Optimization Framework to analyse Stall Induced Vibrations
Chandramouli Santhanam, Riccardo Riva, and Torben Knudsen
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2022-79, https://doi.org/10.5194/wes-2022-79, 2022
Revised manuscript not accepted (discussion: closed, 7 comments)
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As turbine blades get longer and flexible, it is crucial to evaluate stability against Stall Induced Vibrations. This task is however computationally expensive and in this work we propose a framework to evaluate stability against SIV at a reduced computational cost using surrogate models. The framework is demonstrated to study the effect of five inflow variables, and the results show that inflow conditions with a moderate yaw angle, high wind speeds, and negative veer lead to severe SIV.
05 Jul 2022
Deriving atmospheric turbulence intensity from profiling pulsed lidar measurements
Maxime Thiébaut, Marie Cathelain, Salma Yahiaoui, and Ahmed Esmail
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2022-53, https://doi.org/10.5194/wes-2022-53, 2022
Revised manuscript not accepted (discussion: closed, 6 comments)
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The characterization of the turbulence intensity (TI) from profiling lidars measurements is still an active area of research. In this paper, a new method is proposed to derive TI from a WindCube v2.1 lidar. The new method allows for a reduction of TI estimation by a factor of more than 3 in comparison to a method commonly used in the wind energy industry. Moreover, a new configuration of WindCube v2.1 with a sampling rate four times higher than that of the commercial lidar is presented.
02 Jun 2022
Adjoint-Based High Fidelity Concurrent Aerodynamic Design Optimization of Wind Turbine
Sagidolla Batay, Bagdaulet Kamalov, Dinmukhamed Zhangaskanov, Yong Zhao, Dongming Wei, Tongming Zhou, and Xiaohui Su
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2022-12, https://doi.org/10.5194/wes-2022-12, 2022
Revised manuscript not accepted (discussion: closed, 3 comments)
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The primary enhancement is the addition of dihedral as a design variable for optimization, which was not previously considered in wind turbine research. The DAFoam software is implemented and utilized in this investigation, and it is based on the open-source CFD solver OpenFOAM. To the authors’ best knowledge This study represents the first ever work on wind turbine optimization implementing and using the DAFoam to date based on adjoint and RANS solvers with reverse AD technique.
04 May 2022
A New Way to Estimate Maximum Power from Wind Turbines: Linking Newtonian with Action Mechanics
Ivan Kennedy, Migdat Hodzic, Angus Crossan, Nikolas Crossan, Niranjan Acharige, and John Runcie
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2022-22, https://doi.org/10.5194/wes-2022-22, 2022
Revised manuscript not accepted (discussion: closed, 5 comments)
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A more accurate way to calculate power output from wind turbines based on fundamental Newtonian mechanics is proposed for testing. We integrate windward and reverse torques using inputs of rotor dimensions, the angle of incidence and strength of wind impulses on the blade surfaces. Of environmental concern is a prediction of significant heat production by wind turbines.
14 Mar 2022
Adaptive robust observer-based control for structural load mitigation of wind turbines
Edwin Kipchirchir, Manh Hung Do, Jackson Githu Njiri, and Dirk Söffker
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2021-143, https://doi.org/10.5194/wes-2021-143, 2022
Preprint withdrawn (discussion: closed, 3 comments)
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In this work, an adaptive control strategy for reducing structural loading in wind turbine components in varying operating conditions is proposed. The motivation for this work is the growing need for fatigue load alleviation and speed regulation trade-off in modern highly flexible wind turbines. The proposed control strategy shows promising results in blades and tower load mitigation without sacrificing the rotor speed regulation performance, in changing operating conditions and uncertainties.
14 Mar 2022
A theoretical framework for the study of power capture enhancement for wind turbines operating at low wind speeds
Irene Miquelez-Madariaga, Asier Díaz de Corcuera, and Jorge Elso
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2022-18, https://doi.org/10.5194/wes-2022-18, 2022
Publication in WES not foreseen (discussion: closed, 4 comments)
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This work proposes an analysis framework of the control strategy for wind turbines operating at low wind speeds, based on linearized models. Traditionally, this strategy consists on obtaining a generator torque input by a nonlinear feedback of the generator speed. Besides checking for optimality, the linear framework allows to design a feedfoward controllers based on the wind measurements provided by LIDAR sensors. The validity of the linear approximation is tested against a nonlinear simulator.
08 Mar 2022
Gradient-Based Wind Farm Layout Optimization Results Compared with Large-Eddy Simulations
Jared J. Thomas, Christopher J. Bay, Andrew P. J. Stanley, and Andrew Ning
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2022-4, https://doi.org/10.5194/wes-2022-4, 2022
Revised manuscript not accepted (discussion: closed, 5 comments)
Short summary
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We wanted to determine if and how optimization algorithms may be exploiting inaccuracies in the simple models used for wind farm layout optimization. Comparing optimization results from a simple model to large-eddy simulations showed that even a simple model provides enough information for optimizers to find good layouts. However, varying the number of wind directions in the optimization showed that the wind resource discretization can negatively impact the optimization results.
08 Feb 2022
Quantifying the effect of blockage for wind farm layout optimization
Ethan Young, Jeffery Allen, John Jasa, Garrett Barter, and Ryan King
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2022-7, https://doi.org/10.5194/wes-2022-7, 2022
Preprint withdrawn (discussion: closed, 3 comments)
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In this study, we present ways to measure the phenomenon of wind plant blockage, or the the velocity slowdown upstream from a farm, and carry out turbine layout optimizations to reduce this effect. We find that farm-wide measurements provide a better characterization of blockage compared to more localized measurements and that, in the absence of any constraint on total power output, layouts which minimize the effect of blockage are frequently characterized by streamwise alignment of turbines.
03 Feb 2022
An investigation of the applicability of SPIV for the analysis of the dynamics of floating offshore wind platforms
Navid Belvasi, Frances Judge, Jimmy Murphy, Brian Flannery, and Cian Desmond
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2021-128, https://doi.org/10.5194/wes-2021-128, 2022
Revised manuscript not accepted (discussion: closed, 4 comments)
Short summary
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In tank testing, the use of the underwater stereoscopic PIV method to fully characterise the 3D flow field around floating platforms can provide a rich source of validation data and overcome some of the limitations associated with more classical measurement techniques. Therefore, in the current study, the key considerations for using S-PIV for this purpose are discussed; meanwhile, the related studies in the field of quantitative flow measurements are reviewed.
19 Nov 2021
Mid-fidelity simulations and comparisons of five techniques for axial induction control of a wind turbine
Dan Houck, David Maniaci, and Chris L. Kelley
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2021-122, https://doi.org/10.5194/wes-2021-122, 2021
Preprint withdrawn (discussion: closed, 2 comments)
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Like young children without help, wind turbines are bad at sharing. Those that are first in line (most upstream) take all the fresh air leaving little for those downstream. This research shows how turbines can operate to share the wind resource better and what parameters are most important for optimizing this technique. Results indicate that power gains of 10 % can be achieved if upstream turbines are operated differently, which may help operators produce more wind power.
01 Oct 2021
Non-stationarity in correlation matrices for wind turbine SCADA-data and implications for failure detection
Henrik M. Bette, Edgar Jungblut, and Thomas Guhr
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2021-107, https://doi.org/10.5194/wes-2021-107, 2021
Revised manuscript not accepted (discussion: closed, 4 comments)
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We analyse the non-stationarity in Pearson correlation matrices for high frequency wind turbine data. Applying a hierarchichal k-means clustering to a time series of matrices, we distinguish different states, which exhibit distinct correlation structures. These arise from the turbine control system reacting to the current wind speed. We model boundary wind speeds between the different states. Our method enables accounting for the non-stationarity when predicting or analysing turbine failures.
23 Jul 2021
Approaches for predicting wind turbine hub-height turbulence metrics
Hannah Livingston, Nicola Bodini, and Julie K. Lundquist
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2021-68, https://doi.org/10.5194/wes-2021-68, 2021
Preprint withdrawn (discussion: closed, 3 comments)
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In this paper, we assess whether hub-height turbulence can easily be quantified from either other hub-height variables or ground-level measurements in complex terrain. We find a large variability across the three considered locations when trying to model hub-height turbulence intensity and turbulence kinetic energy. Our results highlight the nonlinear and complex nature of atmospheric turbulence, so that more powerful techniques should instead be recommended to model hub-height turbulence.
07 Jul 2021
Dynamic robust active wake control
Stoyan Kanev and Edwin Bot
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2021-71, https://doi.org/10.5194/wes-2021-71, 2021
Publication in WES not foreseen (discussion: closed, 5 comments)
Short summary
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Active Wake Control (AWC) is a strategy for operating wind farms in a cooperative manner to maximize the overall power production. The state-of-the-art approach optimizes AWC for static wind conditions, which is sub-optimal in real-life due to the continuous variations of the wind resource and the very slow dynamics of the yaw system that controls the rotor direction. This work develops dynamic robust AWC that considers realistic operating conditions including variabilities and uncertainties.
22 Jun 2021
Quantifying wind plant blockage under stable atmospheric conditions
Miguel Sanchez Gomez, Julie K. Lundquist, Jeffrey D. Mirocha, Robert S. Arthur, and Domingo Muñoz-Esparza
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2021-57, https://doi.org/10.5194/wes-2021-57, 2021
Revised manuscript not accepted (discussion: closed, 4 comments)
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Winds decelerate upstream of a wind plant as turbines obstruct and extract energy from the flow. This effect is known as wind plant blockage. We assess how atmospheric stability modifies the upstream wind plant blockage. We find stronger stability amplifies this effect. We also explore different approaches to quantifying blockage from field-like observations. We find different methodologies may induce errors of the same order of magnitude as the blockage-induced velocity deficits.
15 Jun 2021
Wind Turbine Ice Detection Using AEP Loss Method – A Case Study
Jia Yi Jin, Timo Karlsson, and Muhammad S. Virk
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2021-55, https://doi.org/10.5194/wes-2021-55, 2021
Preprint withdrawn (discussion: closed, 3 comments)
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In this manuscript, a numerical case study has been presented regarding ice detection and wind resource assessment in ice prone cold regions. Three years SCADA data from a wind park in Arctic region is used for this study. T19IceLossMethod based statistical analysis and Computational Fluid Dynamics (CFD) based numerical simulations are carried out for icing events classification and wind resource assessment, as well as estimation of resultant Annual Energy Production (AEP).
21 May 2021
2D Numerical Simulation Study of Airfoil Performance
Nasser Shelil
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2021-45, https://doi.org/10.5194/wes-2021-45, 2021
Revised manuscript not accepted (discussion: closed, 4 comments)
Short summary
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- Wind power is a promising power generation technology. - The turbulence model has a definitely great influence on the numerical simulation results of wind turbine blade airfoil. - High velocity and low temperature is better conditions to deliver higher power from the wind turbines.
15 Mar 2021
An analytical solution for wind deficit decay behind a wind energy converter using momentum conservation validated by UAS data
Moritz Mauz, Bram van Kesteren, Andreas Platis, Stefan Emeis, and Jens Bange
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2021-21, https://doi.org/10.5194/wes-2021-21, 2021
Preprint withdrawn (discussion: closed, 4 comments)
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The study aims for a computationally inexpensive model describing the wind deficit behind a wind energy converter analytically using some assumptions and basic governing equations of the atmosphere. Thus, the influence of different atmospheric conditions onto the wake development can be studied in the future which is important e.g. in wind park planning. The model is compared to conventional empirical wake models and in-situ UAS measurements captured along the wake at hub height.
10 Mar 2021
Modelling the Wind Turbine Inflow with a Reduced Order Model
based on SpinnerLidar Measurements
Anantha Padmanabhan Kidambi Sekar, Marijn Floris van Dooren, Andreas Rott, and Martin Kühn
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2021-16, https://doi.org/10.5194/wes-2021-16, 2021
Preprint withdrawn (discussion: closed, 3 comments)
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Turbine-mounted lidars performing inflow scans can be used to optimise wind turbine performance and extend their lifetime. This paper introduces a new method to extract wind inflow information from a turbine-mounted scanning SpinnerLidar based on Proper Orthogonal Decomposition. This method offers a balance between simple reconstruction methods and complicated physics-based solvers. The results show that the model can be used for lidar assisted control, loads validation and turbulence studies.
01 Feb 2021
Numerical Investigation of Aerodynamic Performance of Wind
Turbine Airfoils with Ice Accretion
Khaled Yassin, Hassan Kassem, Bernhard Stoevesandt, Thomas Klemme, and Joachim Peinke
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2021-3, https://doi.org/10.5194/wes-2021-3, 2021
Revised manuscript not accepted (discussion: closed, 6 comments)
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When ice forms on wind turbine blades, the smooth surface of the blade becomes rough which changes its aerodynamic performance. So, it is very important to know how to simulate this rough surface since most CFD simulations depend on assuming a smooth surface. This article compares different mathematical models specialized in simulating rough surfaces with results of real ice profiles. The study presents the most accurate model and recommends using it in future airflow simulation of iced blades.
25 Nov 2020
Skewing angle magnet and coil reduced starting torque in a
permanent magnet synchronous generator for a small vertical axis
wind turbine
Priwan Pongwan, Kusumal Chalermnayanont, Mintra Trongtorkarn, Suppachai Jina, and Montri Luengchavanon
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2020-101, https://doi.org/10.5194/wes-2020-101, 2020
Revised manuscript not accepted (discussion: closed, 5 comments)
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The Savonius and H-Darrieus stacked blade can be operated at a wind speed of 1.90 m/s and torque of 1.31 N-m under no-load. We demonstrated that a PMSG electrical generator is able to generate a high starting torque; which is not typical of low speed wind turbines. Using the PMSG with a skewing angle magnet-coil of 15–0 degrees in combination with the blade, the cut-in was found to be at 2.1 m/s in a fully operational vertical wind turbine.
06 Jul 2020
An analytical solution for wind deficit decay behind a wind energy converter using momentum flux conservation validated by UAS data
Moritz Mauz, Bram van Kesteren, Andreas Platis, Stefan Emeis, and Jens Bange
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2020-92, https://doi.org/10.5194/wes-2020-92, 2020
Revised manuscript not accepted (discussion: closed, 4 comments)
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The submitted manuscript suggests an analytical model/approach to connect the near-wake wind deficit with the mid an far-wake deficit. The atmospheric turbulence is considered as the main driver for the wind deficit decay rate in this approach. The analytical solution is backed by a numerical solution of the momentum conservation equation derived from Navier-Stokes equations. In-situ wake UAS measurements are the basis and motivation for the model approach shown in the manuscript.
04 May 2020
Potential of load and O&M costs reductions of Multi Rotor System for the south Baltic Sea
Maciej Karczewski, Piotr Domagalski, Arnoldus van Wingerde, Bernhard Stoevesandt, Peter Jamieson, and Lars Roar Saetran
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2020-23, https://doi.org/10.5194/wes-2020-23, 2020
Revised manuscript not accepted (discussion: closed, 4 comments)
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The paper presents a concept of a multi-rotor system as a floating off-shore wind turbine. The results show that it may be an alternative to conventional wind turbines and even be cheaper in a long run, thus lowering the cost of energy to consumers. It may also solve technological barriers. The motivation for research was the idea of providing a technology vision for regions, where certain local supply chain can be employed to revitalize the shipyard industry while using renewable energy.
30 Mar 2020
Subsea cable management: Failure trending for offshore wind
Charlotte Strang-Moran
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2020-56, https://doi.org/10.5194/wes-2020-56, 2020
Revised manuscript not accepted (discussion: closed, 7 comments)
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Power failure is an issue which is detrimental to both export cables for Offshore Transmission Owners (OFTO) and inter-array cables for wind farm operators. The purpose of this paper is to review current subsea cable failures in the UK sector and to provide an overview of the methodology used to initiate the presented failure trending. The paper will also discuss the importance of accurate data and constraints on the initial findings.
25 Mar 2020
Surrogate models for unsteady aerodynamics using non-intrusive Polynomial Chaos Expansions
Rad Haghi and Curran Crawford
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2020-24, https://doi.org/10.5194/wes-2020-24, 2020
Revised manuscript not accepted (discussion: closed, 5 comments)
23 Mar 2020
Fundamental effect of vibrational mode on vortex-induced vibration in a brimmed diffuser for a wind turbine
Taeyoung Kim, Hiroto Nagai, Nobuhide Uda, and Yuji Ohya
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2020-29, https://doi.org/10.5194/wes-2020-29, 2020
Preprint withdrawn (discussion: closed, 6 comments)
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This study was motivated by a self-induced vibration observed in a wind lens, which is a ring-like diffuser for wind turbines. To reveal the fundamental mechanism of the vortex-induced vibration (VIV) in the brimmed diffuser, a numerical VIV simulation was performed using 3D FEM for modal analysis and 2D CFD for aeroelastic analysis. The result specified the vortex modes and vibration patterns critical to the wind lens structure. Also, this paper suggests how to estimate critical wind speeds.
18 Mar 2020
Comparison of HiL Control Methods for
Wind Turbine System Test Benches
Lennard Kaven, Christian Leisten, Maximilian Basler, Moritz Schlösser, Uwe Jassmann, and Dirk Abel
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2020-42, https://doi.org/10.5194/wes-2020-42, 2020
Preprint withdrawn (discussion: closed, 4 comments)
Short summary
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HiL control methods are required for the design and certification process of wind turbines on system test benches under realistic conditions. By investigating three HiL control methods for the same test bench setup, we outline the results achievable with a basic method. Additionally, we point out why the usage of more complex methods is reasonable to increase the capabilities of HiL operation on system test benches.
24 Feb 2020
Exploitation of the far-offshore wind energy resource by fleets of energy ships. Part B. Cost of energy
Aurélien Babarit, Simon Delvoye, Gaël Clodic, and Jean-Christophe Gilloteaux
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2019-101, https://doi.org/10.5194/wes-2019-101, 2020
Revised manuscript not accepted (discussion: closed, 7 comments)
Short summary
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This paper addresses the topic of far-offshore wind energy exploitation. Far-offshore wind energy exploitation is not feasible with current technology because grid-connection cost, installation cost and O&M cost would be prohibitive. An enabling technology for far-offshore wind energy is the energy ship concept, which has been described, modelled and analyzed in a companion paper. This paper provides a cost model and cost estimates for an energy system based on the energy ship concept.
13 Feb 2020
Demonstration of Offshore Wind Integration with an MMC Test Bench featuring Power-Hardware-in-the-Loop Simulation
Fisnik Loku, Philipp Ruffing, Christina Brantl, and Ralf Puffer
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2020-27, https://doi.org/10.5194/wes-2020-27, 2020
Preprint withdrawn (discussion: closed, 4 comments)
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Demonstration of developed concepts regarding high-voltage DC (HVDC) networks with full-scale components is often not an option due to unavailability and high costs. As alternative, laboratory-scaled demonstrators can be used. Here, the challenges regarding HVDC demonstration with a lab-scaled demonstrator are presented and the behaviour of a test case in stationary and transient operation is analysed based on the wind farm start-up sequence as well as various cases of wind infeed fluctuations.
12 Feb 2020
Accurate loads and velocities on low solidity wind turbines using an improved Blade Element Momentum model
Yassine Ouakki and Abdelaziz Arbaoui
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2020-43, https://doi.org/10.5194/wes-2020-43, 2020
Revised manuscript not accepted (discussion: closed, 3 comments)
Short summary
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It is well known that the classical BEM model fails to accurately predict the loadings and velocities on a wind turbines blade. In this work, an improved BEM model for low solidity wind turbines is proposed by accounting for 3D stall delay and far wake expansion effects. Additionally, the improved BEM equations are solved without the drag force. The results show that the improved BEM model predicts accurately the loading and velocities on the NREL phase VI rotor compared to the classical BEM.
28 Jan 2020
Offshore Wind Energy Resource Assessment from Satellite Data Observations and WRF in Porto Santo Island
Fabiola S. Pereira and Carlos S. Silva
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2020-7, https://doi.org/10.5194/wes-2020-7, 2020
Preprint withdrawn (discussion: closed, 6 comments)
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The work outlines a methodology for combining 20-year time series of surface winds derived from remotely scatterometer observations with results from 10-year wind hindcast from WRF model, in order to acquire and validate reconstructed offshore winds for offshore wind energy resource assessment. The spatial distribution of the mean wind speeds shows that the northern part of the portuguese Porto Santo Island, is characterized by the most interesting wind resource for electricity generation.
20 Jan 2020
A new method for the pragmatic choice of wind models for Wind Resource Assessment in complex terrain
Sarah Barber, Alain Schubiger, Natalie Wagenbrenner, Nicolas Fatras, and Henrik Nordborg
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2019-95, https://doi.org/10.5194/wes-2019-95, 2020
Publication in WES not foreseen (discussion: closed, 2 comments)
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A new method for helping wind modellers choose the most cost-effective model for a given project is developed by applying six different Computational Fluid Dynamics tools to simulate the Bolund Hill experiment and studying appropriate comparison metrics in detail. The results show that this new method is successful, and that it is generally possible to apply it in order to choose the most appropriate model for a given project in advance.
18 Dec 2019
Feasibility study for 100 % renewable energy microgrids in Switzerland
Sarah Barber, Simon Boller, and Henrik Nordborg
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2019-97, https://doi.org/10.5194/wes-2019-97, 2019
Revised manuscript not accepted (discussion: closed, 3 comments)
Short summary
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The growing worldwide level of renewable power generation requires innovative solutions to maintain grid reliability and stability. In this work, twelve sites in Switzerland are chosen for a 100 % renewable energy microgrid feasibility study. For all of these sites, a combination of wind and PV performs consistently better than wind only and PV only. Five of the sites are found to be potentially economically viable, if investors would be prepared to make extra investments of 0.05–0.2 $/kWh.
16 Dec 2019
Performance analysis of a Darrieus-type wind turbine for a series of 4-digit NACA airfoils
Krzysztof Rogowski, Martin Otto Laver Hansen, and Galih Bangga
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2019-98, https://doi.org/10.5194/wes-2019-98, 2019
Preprint withdrawn (discussion: closed, 3 comments)
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I believe that this article contains many valuable tips for engineers that can be useful when constructing medium size vertical-axis wind turbines. Currently, there is still a lack of research on large and medium rotors.
16 Dec 2019
Analysing wind and biomass electricity potential in rural Germany considering local demand in 15-minute intervals
Laura Stößel, Esther Kohl, Björn Roscher, Ralf Schelenz, and Georg Jacobs
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2019-79, https://doi.org/10.5194/wes-2019-79, 2019
Preprint withdrawn (discussion: closed, 4 comments)
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The potential of power generation from biomass to cover the offset between local power demand and supply by solar and wind power is investigated. A model is introduced to simulate power production time series in 15-minute resolution from wind, PV and biomass. The analysis is conducted on the example of five exemplary rural municipalities, each representing one category of rural municipalities in Germany.
12 Nov 2019
Flying UltraSonic – A new way to measure the wind
Martin Hofsäß, Dominique Bergmann, Jan Denzel, and Po Wen Cheng
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2019-81, https://doi.org/10.5194/wes-2019-81, 2019
Revised manuscript not accepted (discussion: closed, 3 comments)
Short summary
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We needed a way to measure wind vectors and turbulence in complex, hard-to-access terrain. We equipped a model helicopter with a standard 3-D ultrasonic anemometer. Due to the hovering capabilities, stationary point measurements are possible. The first measurements were made in flat terrain. A 100 m high stationary wind measuring mast served as reference. The results were investigated in the time domain as well as in the frequency domain.
11 Nov 2019
Improving boundary layer flow simulations over complex terrain by applying a forest parameterization in WRF
Johannes Wagner, Norman Wildmann, and Thomas Gerz
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2019-77, https://doi.org/10.5194/wes-2019-77, 2019
Preprint retracted (discussion: closed, 6 comments)
Short summary
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The impact of a forest parameterization on the simulation of boundary layer flows over complex terrain is investigated. Short- and long-term simulations are run for 12 hours and 1.5 months, respectively, with and without forest parameterization and the results are compared to lidar and meteorological tower observations. The test cases are based on the Perdigao 2017 campaign.
21 Oct 2019
Pathways to bring the costs down of floating offshore wind farms in the Atlantic Area
Juan José Cartelle-Barros, David Cordal-Iglesias, Eugenio Baita-Saavedra, Almudena Filgueira-Vizoso, Bernardino Couñago-Lorenzo, Fernando Vigara, Carlos Cortés, Lara Cerdán, Javier Nieto, José Serna, and Laura Castro-Santos
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2019-73, https://doi.org/10.5194/wes-2019-73, 2019
Publication in WES not foreseen (discussion: closed, 13 comments)
17 Oct 2019
Feedforward-Feedback wake redirection for wind farm control
Steffen Raach, Bart Doekemeijer, Sjoerd Boersma, Jan-Willem van Wingerden, and Po Wen Cheng
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2019-54, https://doi.org/10.5194/wes-2019-54, 2019
Publication in WES not foreseen (discussion: closed, 2 comments)
Short summary
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The presented work combines two control approaches of wake redirection control, feedforward wake redirection and feedback wake redirction. In our previous investigatins the lidar-assisted feedback control was studied and the advantages and disadvantages were discussed. The optimal yaw angles for the wind turbines are precomputed, the feedback takes care of uncertainties and disturbances. The concept is demonstrated in a high fidelity simulation model.
14 Oct 2019
CFD based design of diffuser augmented wind turbines
Ertem Vehid
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2019-75, https://doi.org/10.5194/wes-2019-75, 2019
Preprint withdrawn (discussion: closed, 4 comments)
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Three diffuser augmented wind turbines with separate diffuser concepts were designed by carrying out a series of numeric investigations and a self-developed design optimization process. Single element diffuser was found as the optimum concept based on performance increase and design complexity. The results also highlighted the applicability of diffusers on existing bare rotor geometries. The turbine performances were evaluated by using an edited version of BEM, which was adopted to DAWTs.
30 Sep 2019
The impact of a forest parametrization on coupled WRF-CFD
simulations during the passage of a cold front over the WINSENT
test-site
Daniel Leukauf, Asmae El-Bahlouli, Kjell zum Berge, Martin Schön, Hermann Knaus, and Jens Bange
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2019-68, https://doi.org/10.5194/wes-2019-68, 2019
Revised manuscript not accepted (discussion: closed, 6 comments)
Short summary
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Hilltops are in principle favorable locations for wind turbines due to the increased mean wind speed that can be found over hills. However, the more complex terrain leads to more complex flow conditions and increased turbulence. Numerical simulations are required to understand the flow conditions at sites in hilly terrain. A numerical simulation of the passage of a cold front over the site shows that increased drag caused by the nearby forests must be included in the model.
08 Aug 2019
Study on Multi-Objective Optimization Design and Passive Control
of Wind Turbine Airfoil
Yong Peng, Jun Wang, Wei Wang, and Guoqing Yin
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2019-47, https://doi.org/10.5194/wes-2019-47, 2019
Publication in WES not foreseen (discussion: closed, 2 comments)
Short summary
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In this paper, the multi-objective genetic algorithm is coupled with the class shape transform method to optimize the wind turbine airfoil, and the trailing edge is thickened for the optimized airfoil. The results show that the lift coefficient and lift-to-drag ratio are improved at all angles of attack and the stall is delayed. And the blunt trailing edge airfoil has better lift-to-drag characteristics than the original airfoil and the optimized airfoil.
07 May 2019
Unlocking the Full Potential of Wake Steering: Implementation and Assessment of a Controls-Oriented Model
Christopher J. Bay, Jennifer King, Paul Fleming, Rafael Mudafort, and Luis A. Martínez-Tossas
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2019-19, https://doi.org/10.5194/wes-2019-19, 2019
Preprint withdrawn (discussion: closed, 3 comments)
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This work details a new low-fidelity wake model to be used in determining operational strategies for wind turbines. With the additional physics that this model captures, optimizations have found new control strategies that provide greater increases in performance than previously determined, and these performance increases have been confirmed in high-fidelity simulations. As such, this model can be used in the design and optimization of future wind farms and operational schemes.
02 Apr 2019
OpenOA: An Open-Source Code Base for Operational Analysis of Wind Power Plants
Mike Optis, Jordan Perr-Sauer, Caleb Philips, Anna E. Craig, Joseph C. Y. Lee, Travis Kemper, Shuangwen Sheng, Eric Simley, Lindy Williams, Monte Lunacek, John Meissner, and M. Jason Fields
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2019-12, https://doi.org/10.5194/wes-2019-12, 2019
Preprint withdrawn (discussion: closed, 6 comments)
Short summary
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As global wind capacity continues to grow, the need for accurate operational analyses of a rapidly growing fleet of wind power plants has increased in proportion. To address this need, the National Renewable Energy Laboratory has released OpenOA, an open-source codebase for operational analysis of wind farms. It is envisioned that OpenOA will evolve into a widely used codebase supported by a large group of global wind energy experts. This paper provides a summary of OpenOA.
13 Dec 2018
Minute-Scale Wind Speed Forecasting Using Scanning Lidar Inflow Measurements
Elliot Simon, Michael Courtney, and Nikola Vasiljevic
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2018-71, https://doi.org/10.5194/wes-2018-71, 2018
Publication in WES not foreseen (discussion: closed, 2 comments)
Short summary
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Remotely measured winds upstream of a wind farm presents the opportunity for improving wind energy forecasts on minute timescales. Forward looking information about conditions which advect to some degree downwind provides useful information not available in existing methods. In order to explore this, a field experiment was conduced using scanning lidar to measure winds 7 km ahead of a reference met-mast. Using this dataset, an online learning forecast system has been demonstrated and benchmarked.
10 Sep 2018
A simple improvement of a tip loss model for actuator disc and actuator line simulations
Georg Raimund Pirrung and Maarten Paul van der Laan
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2018-59, https://doi.org/10.5194/wes-2018-59, 2018
Revised manuscript not accepted (discussion: closed, 4 comments)
Short summary
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Wind turbine loading decreases towards the blade tip due to the velocities induced by the tip vortex and the spanwise flow. It has been shown that the tip loss factor applied on the aerodynamic forces should be different for the axial and tangential loading of the turbine due to the rotation of the resulting force vector caused by the induced velocity. The present article contains the derivation of a simple correction for the tangential load factor that takes this rotation into account.
06 Aug 2018
Towards the North Sea wind power revolution
Jens N. Sørensen and Gunner C. Larsen
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2018-53, https://doi.org/10.5194/wes-2018-53, 2018
Preprint withdrawn (discussion: closed, 4 comments)
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The work assesses the potential of a massive exploitation of offshore wind power in the North Sea by combining a meteorological model with a cost model including a bathymetric analysis of the water depth of the North Sea. As an overall finding, it is shown that the electrical power demand of Europe can be fulfilled by exploiting an area corresponding to about 1/3 of the North Sea with 100.000 wind turbines of generator size 13 MW on water depths up to 45 m to a cost price of about 7.5 €cents/kWh.
03 Jul 2018
Scale-adaptive simulation of wind turbines, and its verification with respect to wind tunnel measurements
Jiangang Wang, Chengyu Wang, Filippo Campagnolo, and Carlo L. Bottasso
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2018-47, https://doi.org/10.5194/wes-2018-47, 2018
Revised manuscript has not been submitted (discussion: closed, 2 comments)
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This paper describes a Scale Adaptive Simulation (SAS) approach for
the numerical simulation of wind turbines and their wakes. The SAS
formulation is found to be about one order of magnitude faster than
a classical LES approach. The simulation models are compared to
each other and with experimental measurements obtained with scaled
wind turbines in a boundary layer wind tunnel.
24 May 2018
Hybrid adaptive control for variable-speed variable-pitch wind
energy systems using general regression neural network
Xiuxing Yin
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2018-19, https://doi.org/10.5194/wes-2018-19, 2018
Preprint retracted (discussion: closed, 4 comments)
14 May 2018
Control-oriented Linear Dynamic Wind Farm Flow and Operation
Model
Jonas Kazda and Nicolaos Antonio Cutululis
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2018-29, https://doi.org/10.5194/wes-2018-29, 2018
Preprint retracted (discussion: closed, 6 comments)
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This work presents the Dynamic Flow Predictor, which was developed with the objective to provide predictions of wind speed and turbine power in a wind farm using a computationally effective, control-oriented model. Dynamic simulations of test wind farms have demonstrated the accuracy of the Dynamic Flow Predictor. The employed modelling approach in the Dynamic Flow Predictor is well suited for the use in wind farm control, wind turbine control and as a virtual wind turbine sensor.
26 Apr 2018
Optimal Output Feedback H∞ Torque Control of a Wind Turbine Rotor using a Parametrically Scheduled Model
Dana Martin, Kathryn Johnson, Christopher Bay, Daniel Zalkind, Lucy Pao, Meghan Kaminski, and Eric Loth
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2018-27, https://doi.org/10.5194/wes-2018-27, 2018
Revised manuscript not accepted (discussion: closed, 4 comments)
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The paper provides an account of the synthesis of a Linear Parameter Varying (LPV) controller and its improved performance as applied to a down-wind, two bladed, per-aligned rotor. The analysis of controller performance during a turbulent inflow with a mean wind speed of 4 m/s show increased performance in terms of better tip speed ratio tracking and reduced fatigue damage to various turbine components. The results provide a basis of LPV control and its ability to increase turbine lifetime.
03 Apr 2018
Effect of Atmospheric Stability on the Wind Resource extrapolating models for large capacity Wind Turbines: A Comparative Analysis of Power Law, Log Law and Deaves and Harris mode
Pramod Kumar Sharma, Vilas Warudkar, and Siraj Ahmed
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2018-16, https://doi.org/10.5194/wes-2018-16, 2018
Preprint retracted (discussion: closed, 8 comments)
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Due to increasing demand of energy, Wind resource prediction has become a crucial issue markedly for energy investors to accurately analyze the wind speed at different hub height of WT. This is very much necessary during the feasibility study to abate the cost of wind farm installation. There are many researchers who worked on different wind extrapolating models such as PL, LogL, LogLL and DH.
12 Feb 2018
Wind farm power production assessment: a comparative analysis of two actuator disc methods and two analytical wake models
Nikolaos Simisiroglou, Heracles Polatidis, and Stefan Ivanell
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2018-8, https://doi.org/10.5194/wes-2018-8, 2018
Preprint withdrawn (discussion: closed, 4 comments)
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The aim of the present study is to perform a comparative analysis of two actuator disc methods (ACD) and two analytical wake models for wind farm power production assessment. To do so wind turbine power production data from the Lillgrund offshore wind farm in Sweden is used. The measured power production for individual wind turbines is compared with results from simulations, done in the WindSim software.
15 Jan 2018
Analysis of Different Gray Zone Treatments in WRF-LES Real Case Simulations
Paula Doubrawa, Alex Montornès, Rebecca J. Barthelmie, Sara C. Pryor, and Pau Casso
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2017-61, https://doi.org/10.5194/wes-2017-61, 2018
Preprint withdrawn (discussion: closed, 2 comments)
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We perform time-resolved, high-resolution simulations of the atmospheric boundary layer with a numerical weather prediction model. The downscaling is done within the model by defining nested domains, and we investigate different ways of treating turbulence modeling at intermediate spatial scales in which traditional turbulence parameterizations are inadequate. We focus on quantities of interest to wind energy and compare the simulations with measurements collected at a complex-terrain site.
22 Nov 2017
Numerical airfoil catalogue including 360° airfoil polars and aeroacoustic footprints
Manfred Imiela, Benjamin Faßmann, Gerrit Heilers, and Gunther Wilke
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2017-51, https://doi.org/10.5194/wes-2017-51, 2017
Revised manuscript not accepted (discussion: closed, 4 comments)
12 Oct 2017
Aerodynamic Performance of the NREL S826 Airfoil in Icing Conditions
Julie Krøgenes, Lovisa Brandrud, Richard Hann, Jan Bartl, Tania Bracchi, and Lars Sætran
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2017-39, https://doi.org/10.5194/wes-2017-39, 2017
Preprint withdrawn (discussion: closed, 4 comments)
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Leading edge ice accretion causes significant performance degradation to wind power installations in cold climate areas. This study focuses on the effect of three typical ice shapes; rime ice, glaze ice and a mixed ice. Experiments were conducted in the low speed wind tunnel at NTNU and compared with ANSYS Fluent CFD analyses. Results show a reduction on lift and an increase in drag for all ice cases, most severely for the mixed ice with it's horn-like shape.
22 Aug 2017
Numerical simulation of non-neutral forest canopy flows at a site in North-Eastern France
Cian J. Desmond, Simon J. Watson, Christiane Montavon, and Jimmy Murphy
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2017-34, https://doi.org/10.5194/wes-2017-34, 2017
Revised manuscript not accepted (discussion: closed, 4 comments)
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The flow over densely forested terrain under neutral and non-neutral conditions is considered using commercially available Computational Fluid Dynamics software. Results are validated against data from a site in North-Eastern France. It is shown that the effects of both neutral and stable atmospheric stratifications can be modelled numerically using state of the art methodologies whilst unstable stratifications remain elusive.
13 Feb 2017
Full HAWT rotor CFD simulations using different RANS turbulence models compared with actuator disk and experimental measurements
Nikolaos Stergiannis, Jeroen van Beeck, and Mark C. Runacres
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2017-6, https://doi.org/10.5194/wes-2017-6, 2017
Revised manuscript not accepted (discussion: closed, 4 comments)
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The development of large-scale wind energy projects has created the demand for increasingly accurate and efficient models that limit a project's uncertainties and risk. Wake effects are of great importance and are relevant for the optimization of wind farms. In the present paper, different Computational Fluid Dynamics (CFD) simulations are investigated and compared with single wake measurements of a wind turbine in a wind tunnel. Results show that CFD can predict the wake effects downstream.
12 Jan 2017
Flow angle measurement of a yawed turbine and comparison to
models
Tyler Gallant and David A. Johnson
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2016-57, https://doi.org/10.5194/wes-2016-57, 2017
Revised manuscript has not been submitted (discussion: closed, 4 comments)
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The torque generated by a wind turbine blade is dependent on several parameters, one of which is the angle of attack. When the turbine is misaligned with the oncoming wind, direction (yawed) the angle of attack changes significantly. Experiments have been conducted to measure the angle of attack as a function of several parameters. The quality of results indicates the potential of the developed instrument for wind turbine measurements.
22 Dec 2016
Methodology for the engineering calculation of flaps on Wind Turbines using BEM codes
Maria Aparicio-Sanchez, Alvaro Gonzalez-Salcedp, Sugoi Gomez-Iradi, and Xabier Munduate
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2016-50, https://doi.org/10.5194/wes-2016-50, 2016
Preprint withdrawn (discussion: closed, 6 comments)
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The use of the flaps is one of the options to reduce the equivalent loads or to increase the power in large wind turbines. This paper presents a methodology to simulate the performance of the blades with these aerodynamic devices. This method presents important advantages with respect to CFD in terms of computational effort and leads to similar results.
20 Dec 2016
Updating BEM models with 3D rotor CFD data
Marc S. Schneider, Jens Nitzsche, and Holger Hennings
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2016-51, https://doi.org/10.5194/wes-2016-51, 2016
Preprint withdrawn (discussion: closed, 4 comments)
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In this work, the results of high-fidelity flow simulations are used to improve a fast, low-fidelity engineering model. This can improve the accuracy of aerodynamic simulations for wind turbines while keeping the computational effort low. The high-fidelity method consumes many hours to obtain a result, whereas the updated engineering model produces almost the same result in a matter of seconds.
14 Dec 2016
Structural optimisation of wind turbine towers based on finite
element analysis and genetic algorithm
Lin Wang, Athanasios Kolios, Maria Martinez Luengo, and Xiongwei Liu
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2016-41, https://doi.org/10.5194/wes-2016-41, 2016
Preprint withdrawn (discussion: closed, 4 comments)
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In this work, a structural optimisation model for wind turbine towers has been developed based on a combined parametric FEA (finite element analysis) and GA (genetic algorithm) model. It is demonstrated that the proposed structural optimisation model is capable of accurately and effectively achieving an optimal structural design of wind turbine towers, which significantly improves the efficiency of structural optimisation of wind turbine towers.
17 Nov 2016
Stochastic Wake Modeling Based on POD Analysis
David Bastine, Lukas Vollmer, Matthias Wächter, and Joachim Peinke
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2016-38, https://doi.org/10.5194/wes-2016-38, 2016
Revised manuscript not accepted (discussion: closed, 4 comments)
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Modeling of wind turbine wakes plays a key role in the maximization of the power output and lifetime of wind turbines in wind farms. In order to capture important dynamic and turbulent aspects of the wake, a new stochastic modeling approach is presented in this work. The resulting new kind of stochastic wake model captures important characteristics of loads which act on wind turbines in the wake. It might therefore be of great use for the planing and controlling of wind farms.
28 Sep 2016
FLOWSTAR-Energy: a high resolution wind farm wake model
Amy Stidworthy and David Carruthers
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2016-34, https://doi.org/10.5194/wes-2016-34, 2016
Manuscript not accepted for further review (discussion: closed, 6 comments)
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FLOWSTAR-Energy is a new practical model for predicting wind energy production from both onshore and offshore wind farms, allowing for the effects of topography, atmospheric stability and turbine wakes on the airflow. It includes an innovative model of wake interaction which exploits similarities in the behaviour of a wake and a plume of passive gas. Comparisons between model predictions and measurements from three sites show good agreement especially where stability effects are accounted for.
07 Sep 2016
Detection of ice mass based on the natural frequencies of wind
turbine blade
Sudhakar Gantasala, Jean-Claude Luneno, and Jan-Olov Aidanpaa
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2016-30, https://doi.org/10.5194/wes-2016-30, 2016
Manuscript not accepted for further review (discussion: closed, 4 comments)
11 Jul 2016
Assessing Spacing Impact on the Wind Turbine Array Boundary Layer via Proper Orthogonal Decomposition
Naseem Ali, Nicholas Hamilton, and Raúl Bayáon Cal
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2016-23, https://doi.org/10.5194/wes-2016-23, 2016
Revised manuscript not accepted (discussion: closed, 4 comments)
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The effect of the density of turbines on the wake recovery is important. However, the impact of the tight spacing is still not fully understood. Here, we used proper orthogonal decomposition tool to analyze this impact. Different streamwise and spanwise spacings are chosen to make this work robust. Thus, the power measurements are also applied to investigate the spacing impact.
18 Apr 2016
Feasibility of small wind turbines in Ontario: Integrating power curves with wind trends
Masaō Ashtine, Richard Bello, and Kaz Higuchi
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2016-9, https://doi.org/10.5194/wes-2016-9, 2016
Preprint retracted (discussion: closed, 5 comments)
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Our paper represents much needed research into changing wind patterns across the province of Ontario, Canada, complemented by incorporating observed wind turbine performance. Small wind turbines have been largely neglected in long-term climate research and this paper focuses on the atmospheric heights of 10 and 30 m to better inform the small wind turbine industry. Novel use of real power curves highlight the most productive seasons and regions for the implementation of small wind turbines.