Articles | Volume 7, issue 5
https://doi.org/10.5194/wes-7-1827-2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/wes-7-1827-2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
08 Sep 2022
Research article |
| 08 Sep 2022
| 08 Sep 2022
Experimental analysis of the dynamic inflow effect due to coherent gusts
Frederik Berger
CORRESPONDING AUTHOR
ForWind – Center for Wind Energy Research, University of Oldenburg, Institute of Physics, Küpkersweg 70, 26127 Oldenburg, Germany
Lars Neuhaus
ForWind – Center for Wind Energy Research, University of Oldenburg, Institute of Physics, Küpkersweg 70, 26127 Oldenburg, Germany
David Onnen
ForWind – Center for Wind Energy Research, University of Oldenburg, Institute of Physics, Küpkersweg 70, 26127 Oldenburg, Germany
Michael Hölling
ForWind – Center for Wind Energy Research, University of Oldenburg, Institute of Physics, Küpkersweg 70, 26127 Oldenburg, Germany
Gerard Schepers
TNO Energy Transition, 1755 LE Petten, the Netherlands
Institute of Engineering, Hanze University of Applied Sciences, 9747 AS Groningen, the Netherlands
Martin Kühn
ForWind – Center for Wind Energy Research, University of Oldenburg, Institute of Physics, Küpkersweg 70, 26127 Oldenburg, Germany
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Wind Energ. Sci., 6, 983–996, https://doi.org/10.5194/wes-6-983-2021, https://doi.org/10.5194/wes-6-983-2021, 2021
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Jörge Schneemann, Frauke Theuer, Andreas Rott, Martin Dörenkämper, and Martin Kühn
Wind Energ. Sci., 6, 521–538, https://doi.org/10.5194/wes-6-521-2021, https://doi.org/10.5194/wes-6-521-2021, 2021
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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Preprint withdrawn
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Sirko Bartholomay, Tom T. B. Wester, Sebastian Perez-Becker, Simon Konze, Christian Menzel, Michael Hölling, Axel Spickenheuer, Joachim Peinke, Christian N. Nayeri, Christian Oliver Paschereit, and Kilian Oberleithner
Wind Energ. Sci., 6, 221–245, https://doi.org/10.5194/wes-6-221-2021, https://doi.org/10.5194/wes-6-221-2021, 2021
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Frauke Theuer, Marijn Floris van Dooren, Lueder von Bremen, and Martin Kühn
Wind Energ. Sci., 5, 1449–1468, https://doi.org/10.5194/wes-5-1449-2020, https://doi.org/10.5194/wes-5-1449-2020, 2020
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Niels Adema, Menno Kloosterman, and Gerard Schepers
Wind Energ. Sci., 5, 577–590, https://doi.org/10.5194/wes-5-577-2020, https://doi.org/10.5194/wes-5-577-2020, 2020
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Jörge Schneemann, Andreas Rott, Martin Dörenkämper, Gerald Steinfeld, and Martin Kühn
Wind Energ. Sci., 5, 29–49, https://doi.org/10.5194/wes-5-29-2020, https://doi.org/10.5194/wes-5-29-2020, 2020
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We analysed the impact of these so-called cluster wakes on a distant wind farm using remote-sensing wind measurements and power production data.
Cluster wakes caused power losses up to 55 km downstream in certain atmospheric states.
A better understanding of cluster wake effects reduces uncertainties in offshore wind resource assessment and improves offshore areal planning.
Róbert Ungurán, Vlaho Petrović, Lucy Y. Pao, and Martin Kühn
Wind Energ. Sci., 4, 677–692, https://doi.org/10.5194/wes-4-677-2019, https://doi.org/10.5194/wes-4-677-2019, 2019
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Mehdi Vali, Vlaho Petrović, Gerald Steinfeld, Lucy Y. Pao, and Martin Kühn
Wind Energ. Sci., 4, 139–161, https://doi.org/10.5194/wes-4-139-2019, https://doi.org/10.5194/wes-4-139-2019, 2019
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Andreas Rott, Bart Doekemeijer, Janna Kristina Seifert, Jan-Willem van Wingerden, and Martin Kühn
Wind Energ. Sci., 3, 869–882, https://doi.org/10.5194/wes-3-869-2018, https://doi.org/10.5194/wes-3-869-2018, 2018
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Niko Mittelmeier and Martin Kühn
Wind Energ. Sci., 3, 395–408, https://doi.org/10.5194/wes-3-395-2018, https://doi.org/10.5194/wes-3-395-2018, 2018
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Upwind horizontal axis wind turbines need to be aligned with the main wind direction to maximize energy yield. This paper presents new methods to improve turbine alignment and detect changes during operational lifetime with standard nacelle met mast instruments. The flow distortion behind the rotor is corrected with a multilinear regression model and two alignment changes are detected with an accuracy of ±1.4° within 3 days of operation after the change is introduced.
Jan Bartl, Franz Mühle, Jannik Schottler, Lars Sætran, Joachim Peinke, Muyiwa Adaramola, and Michael Hölling
Wind Energ. Sci., 3, 329–343, https://doi.org/10.5194/wes-3-329-2018, https://doi.org/10.5194/wes-3-329-2018, 2018
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Wake steering by yawing a wind turbine offers great potential to increase the wind farm power production. A model scale experiment in a controlled wind tunnel environment has been performed to map the wake flow's complex velocity distribution for different inflow conditions. A non-uniform sheared inflow was observed to affect the wake flow only insignificantly. The level of turbulent velocity fluctuations in the inflow, however, influenced the wake's velocity distribution to a higher degree.
Laura Valldecabres, Alfredo Peña, Michael Courtney, Lueder von Bremen, and Martin Kühn
Wind Energ. Sci., 3, 313–327, https://doi.org/10.5194/wes-3-313-2018, https://doi.org/10.5194/wes-3-313-2018, 2018
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This paper focuses on the use of scanning lidars for very short-term forecasting of wind speeds in a near-coastal area. An extensive data set of offshore lidar measurements up to 6 km has been used for this purpose. Using dual-doppler measurements, the topographic characteristics of the area have been modelled. Assuming Taylor's frozen turbulence and applying the topographic corrections, we demonstrate that we can forecast wind speeds with more accuracy than the benchmarks persistence or ARIMA.
Jannik Schottler, Jan Bartl, Franz Mühle, Lars Sætran, Joachim Peinke, and Michael Hölling
Wind Energ. Sci., 3, 257–273, https://doi.org/10.5194/wes-3-257-2018, https://doi.org/10.5194/wes-3-257-2018, 2018
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In this work, the wake flows behind two different model wind turbines were investigated in wind tunnel experiments user laser Doppler anemometry. It was found that the width of the wake flow is significantly dependent on the quantities examined, becoming much wider when taking higher-order statistics into account. This effect is stable against yaw misalignment and thus affects not only wind farm layout optimizations but also the applicability of active wake steering methods.
Lukas Vollmer, Gerald Steinfeld, and Martin Kühn
Wind Energ. Sci., 2, 603–614, https://doi.org/10.5194/wes-2-603-2017, https://doi.org/10.5194/wes-2-603-2017, 2017
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A model chain to simulate changing atmospheric conditions at the location of an offshore wind farm is introduced and validated. The methodology is used to simulate the wind flow upstream and downstream of an offshore wind turbine of the German wind farm Alpha ventus. The model results show a good agreement with wind measurements from the met mast that is located at the wind farm and with remote sensing measurements of the horizontal wind field.
Davide Trabucchi, Lukas Vollmer, and Martin Kühn
Wind Energ. Sci., 2, 569–586, https://doi.org/10.5194/wes-2-569-2017, https://doi.org/10.5194/wes-2-569-2017, 2017
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The wakes of wind turbines cause losses in the energy production of a wind farm. The accuracy of models applied to predict wake losses is a key factor for new wind projects. This paper presents an engineering wake model that can simulate merging wakes on the basis of physical principles. We used high-fidelity simulations of merging wakes to assess this model and found a better agreement with the reference than commonly used models implementing the superposition of individual wakes.
Niko Mittelmeier, Julian Allin, Tomas Blodau, Davide Trabucchi, Gerald Steinfeld, Andreas Rott, and Martin Kühn
Wind Energ. Sci., 2, 477–490, https://doi.org/10.5194/wes-2-477-2017, https://doi.org/10.5194/wes-2-477-2017, 2017
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Jannik Schottler, Agnieszka Hölling, Joachim Peinke, and Michael Hölling
Wind Energ. Sci., 2, 439–442, https://doi.org/10.5194/wes-2-439-2017, https://doi.org/10.5194/wes-2-439-2017, 2017
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Recently, the concept of intentional derating of single wind turbines in order to increase the energy yield of a wind farm has been studied intensively. Although the potential seems promising, the effects of atmospheric conditions need to be understood in greater detail. This study shows a strong influence of vertical velocity gradients on the power output of two model wind turbines, whereas the upstream turbine is derated by an intentional misalignment of the rotor and the inflow.
Marijn Floris van Dooren, Filippo Campagnolo, Mikael Sjöholm, Nikolas Angelou, Torben Mikkelsen, and Martin Kühn
Wind Energ. Sci., 2, 329–341, https://doi.org/10.5194/wes-2-329-2017, https://doi.org/10.5194/wes-2-329-2017, 2017
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We conducted measurements in a wind tunnel with the remote sensing technique lidar to map the flow around a row of three model wind turbines. Two lidars were positioned near the wind tunnel walls to measure the two-dimensional wind vector over a defined scanning line or area without influencing the flow itself. A comparison of the lidar measurements with a hot-wire probe and a thorough uncertainty analysis confirmed the usefulness of lidar technology for such flow measurements in a wind tunnel.
Niko Mittelmeier, Tomas Blodau, and Martin Kühn
Wind Energ. Sci., 2, 175–187, https://doi.org/10.5194/wes-2-175-2017, https://doi.org/10.5194/wes-2-175-2017, 2017
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Efficient detection of wind turbines operating below their expected power output and immediate corrections help maximize asset value. The method presented estimates the environmental conditions from turbine states and uses pre-calculated power lookup tables from a numeric wake model to predict the expected power output. Deviations between the expected and the measured power output are an indication of underperformance. A demonstration of the method's ability to detect underperformance is given.
Jannik Schottler, Nico Reinke, Agnieszka Hölling, Jonathan Whale, Joachim Peinke, and Michael Hölling
Wind Energ. Sci., 2, 1–13, https://doi.org/10.5194/wes-2-1-2017, https://doi.org/10.5194/wes-2-1-2017, 2017
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To what extent turbulence characteristics of wind in the atmosphere transfer to wind turbines in terms of power, loads, etc. is of great interest throughout the research community. An experimental approach using a model wind turbine at laboratory scale was used in a wind tunnel study. It is shown that the gustiness of the wind remains present in the wind turbine data, stressing the importance of including those wind characteristics in industry standards and when designing wind turbines.
Lukas Vollmer, Gerald Steinfeld, Detlev Heinemann, and Martin Kühn
Wind Energ. Sci., 1, 129–141, https://doi.org/10.5194/wes-1-129-2016, https://doi.org/10.5194/wes-1-129-2016, 2016
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The wake flow downstream of yaw misaligned wind turbines is studied in numeric simulations of different atmospheric turbulence and shear conditions. We find that the average trajectory of the wake as well as the variation about this average is influenced by the thermal stability of the atmosphere. The results suggest that an intentional intervention in the yaw control of individual turbines to increase overall wind farm performance might be not successful during unstable thermal conditions.
Juan José Trujillo, Janna Kristina Seifert, Ines Würth, David Schlipf, and Martin Kühn
Wind Energ. Sci., 1, 41–53, https://doi.org/10.5194/wes-1-41-2016, https://doi.org/10.5194/wes-1-41-2016, 2016
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We present the analysis of the trajectories followed by the wind, in the immediate vicinity, behind an offshore wind turbine and their dependence on its yaw misalignment. We apply wake tracking on wind fields measured with a lidar (light detection and ranging) system located at the nacelle of the wind turbine and pointing downstream. The analysis reveals discrepancies of the estimated mean wake paths against theoretical and wind tunnel experiments using different wake-tracking techniques.
Related subject area
Thematic area: Fluid mechanics | Topic: Wind turbine aerodynamics
On the characteristics of the wake of a wind turbine undergoing large motions caused by a floating structure: an insight based on experiments and multi-fidelity simulations from the OC6 project Phase III
Forced-motion simulations of vortex-induced vibrations of wind turbine blades – a study of sensitivities
Towards smart blades for vertical axis wind turbines: different airfoil shapes and tip speed ratios
An analytical linear two-dimensional Actuator Disc Model and comparisons with CFD simulations
Numerical study of the unsteady blade root aerodynamics of a 2 MW wind turbine equipped with vortex generators
Developing a Digital Twin Framework for Wind Tunnel Testing: Validation of Turbulent Inflow and Airfoil Load Applications
Generalized analytical body force model for actuator disc computations of wind turbines
Field data based validation of an aero-servo-elastic solver for high-fidelity LES of industrial wind turbines
Nonlinear inviscid aerodynamics of a wind turbine rotor in surge, sway, and yaw motions using a free-wake panel method
OC6 project Phase III: validation of the aerodynamic loading on a wind turbine rotor undergoing large motion caused by a floating support structure
A simple vortex model applied to an idealized rotor in sheared inflow
Comparison of free vortex wake and blade element momentum results against large-eddy simulation results for highly flexible turbines under challenging inflow conditions
Numerical simulations of ice accretion on wind turbine blades: are performance losses due to ice shape or surface roughness?
Progress in the validation of rotor aerodynamic codes using field data
A comparison of dynamic inflow models for the blade element momentum method
Multiple limit cycle amplitudes in high-fidelity predictions of standstill wind turbine blade vibrations
Model tests of a 10 MW semi-submersible floating wind turbine under waves and wind using hybrid method to integrate the rotor thrust and moments
Atmospheric rotating rig testing of a swept blade tip and comparison with multi-fidelity aeroelastic simulations
A WaveNet-based fully stochastic dynamic stall model
High-Reynolds-number wind turbine blade equipped with root spoilers – Part 2: Impact on energy production and turbine lifetime
Wind tunnel investigation of the aerodynamic response of two 15 MW floating wind turbines
Vertical wake deflection for floating wind turbines by differential ballast control
High-fidelity aeroelastic analyses of wind turbines in complex terrain: fluid–structure interaction and aerodynamic modeling
Development of a wireless, non-intrusive, MEMS-based pressure and acoustic measurement system for large-scale operating wind turbine blades
How should the lift and drag forces be calculated from 2-D airfoil data for dihedral or coned wind turbine blades?
Stefano Cioni, Francesco Papi, Leonardo Pagamonci, Alessandro Bianchini, Néstor Ramos-García, Georg Pirrung, Rémi Corniglion, Anaïs Lovera, Josean Galván, Ronan Boisard, Alessandro Fontanella, Paolo Schito, Alberto Zasso, Marco Belloli, Andrea Sanvito, Giacomo Persico, Lijun Zhang, Ye Li, Yarong Zhou, Simone Mancini, Koen Boorsma, Ricardo Amaral, Axelle Viré, Christian W. Schulz, Stefan Netzband, Rodrigo Soto-Valle, David Marten, Raquel Martín-San-Román, Pau Trubat, Climent Molins, Roger Bergua, Emmanuel Branlard, Jason Jonkman, and Amy Robertson
Wind Energ. Sci., 8, 1659–1691, https://doi.org/10.5194/wes-8-1659-2023, https://doi.org/10.5194/wes-8-1659-2023, 2023
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Simulations of different fidelities made by the participants of the OC6 project Phase III are compared to wind tunnel wake measurements on a floating wind turbine. Results in the near wake confirm that simulations and experiments tend to diverge from the expected linearized quasi-steady behavior when the reduced frequency exceeds 0.5. In the far wake, the impact of platform motion is overestimated by simulations and even seems to be oriented to the generation of a wake less prone to dissipation.
Christian Grinderslev, Felix Houtin-Mongrolle, Niels Nørmark Sørensen, Georg Raimund Pirrung, Pim Jacobs, Aqeel Ahmed, and Bastien Duboc
Wind Energ. Sci., 8, 1625–1638, https://doi.org/10.5194/wes-8-1625-2023, https://doi.org/10.5194/wes-8-1625-2023, 2023
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In standstill conditions wind turbines are at risk of vortex-induced vibrations (VIVs). VIVs can become large and lead to significant fatigue of the wind turbine structure over time. Thus it is important to have tools that can accurately compute this complex phenomenon. This paper studies the sensitivities to the chosen models of computational fluid dynamics (CFD) simulations when modelling VIVs and finds that much care is needed when setting up simulations, especially for specific flow angles.
Mohammad Rasoul Tirandaz, Abdolrahim Rezaeiha, and Daniel Micallef
Wind Energ. Sci., 8, 1403–1424, https://doi.org/10.5194/wes-8-1403-2023, https://doi.org/10.5194/wes-8-1403-2023, 2023
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Vertical axis wind turbines experience a variation of torque and power throughout their rotation. Traditional non-morphing blades are intrinsically not able to respond to this variation, resulting in a turbine which has suboptimal performance. In principle, it is possible to have a morphing blade that adapts to the blade's rotation and changes its geometry in such a way as to optimise the performance of the turbine. This paper addresses the question of how such blade should morph as it rotates.
Helge Aagaard Madsen
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2023-99, https://doi.org/10.5194/wes-2023-99, 2023
Revised manuscript accepted for WES
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We present a linear analytical solution for a two-dimensional (2-D) actuator disc (AD) for a plane disc, a yawed disc and a coned disc. Comparisons of the 2-D model with three-dimensional CFD AD simulations for a circular yawed disc and with an axis-symmetric CFD simulation of a coned disc show good correlation for the normal velocity component to the disc. This indicates that the 2-D AD model could form the basis for a consistent, simple new rotor induction model
Ferdinand Seel, Thorsten Lutz, and Ewald Krämer
Wind Energ. Sci., 8, 1369–1385, https://doi.org/10.5194/wes-8-1369-2023, https://doi.org/10.5194/wes-8-1369-2023, 2023
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Vortex generators are evaluated on a 2 MW wind turbine rotor blade by computational fluid dynamic methods. Those devices delay flow separation on the airfoils and thus increase their efficiency. On the wind turbine blade, rotational phenomena (e.g. rotational augmentation) appear and interact with the vortices from the vortex generators. The understanding of those interactions is crucial in order to optimise the placement of the vortex generators and evaluate their real efficiency on the blade.
Rishabh Mishra, Emmanuel Guilmineau, Ingrid Neunaber, and Caroline Braud
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2023-70, https://doi.org/10.5194/wes-2023-70, 2023
Revised manuscript under review for WES
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In this study, we investigated how turbulence affects wind turbines by studying the aerodynamics of a 2d blade section derived from a real wind turbine. Using wind tunnel measurements and simulations, we found the correct method to simulate turbulence and accurately replicated experimental results. This improves our understanding of wind turbine performance.
Jens N. Sørensen
Wind Energ. Sci., 8, 1017–1027, https://doi.org/10.5194/wes-8-1017-2023, https://doi.org/10.5194/wes-8-1017-2023, 2023
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The paper presents a simple analytical model that, with surprisingly good accuracy, represents the loading for virtually any horizontal axis wind turbine, independent of size and operating regime. The aim of the model is to have a simple tool that may represent the loading of any wind turbine without having access to the details regarding the specific geometry and airfoil data, information that is normally kept confidential by the manufacturer of the turbine.
Etienne Muller, Simone Gremmo, Félix Houtin-Mongrolle, Bastien Duboc, and Pierre Bénard
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2023-41, https://doi.org/10.5194/wes-2023-41, 2023
Revised manuscript accepted for WES
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This article presents an advanced tool designed for the high-fidelity and high-performance simulation of operating wind turbines, allowing for instance to compute a blade deformation, as well as of the surrounding airflow. As this tool relies on coupling two existing codes, the coupling strategy is first described in depth. The article then presents the verification of the coupled code on simplified configurations. Finally, the code results are compared to field data for validation purposes.
André F. P. Ribeiro, Damiano Casalino, and Carlos S. Ferreira
Wind Energ. Sci., 8, 661–675, https://doi.org/10.5194/wes-8-661-2023, https://doi.org/10.5194/wes-8-661-2023, 2023
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Floating offshore wind turbines move due to not having a rigid foundation. Hence, as the blades rotate they experience more complex aerodynamics than standard onshore wind turbines. In this paper, we show computational simulations of a wind turbine rotor moving in various ways and quantify the effects of the motion in the forces acting on the blades. We show that these forces behave in nonlinear ways in some cases.
Roger Bergua, Amy Robertson, Jason Jonkman, Emmanuel Branlard, Alessandro Fontanella, Marco Belloli, Paolo Schito, Alberto Zasso, Giacomo Persico, Andrea Sanvito, Ervin Amet, Cédric Brun, Guillén Campaña-Alonso, Raquel Martín-San-Román, Ruolin Cai, Jifeng Cai, Quan Qian, Wen Maoshi, Alec Beardsell, Georg Pirrung, Néstor Ramos-García, Wei Shi, Jie Fu, Rémi Corniglion, Anaïs Lovera, Josean Galván, Tor Anders Nygaard, Carlos Renan dos Santos, Philippe Gilbert, Pierre-Antoine Joulin, Frédéric Blondel, Eelco Frickel, Peng Chen, Zhiqiang Hu, Ronan Boisard, Kutay Yilmazlar, Alessandro Croce, Violette Harnois, Lijun Zhang, Ye Li, Ander Aristondo, Iñigo Mendikoa Alonso, Simone Mancini, Koen Boorsma, Feike Savenije, David Marten, Rodrigo Soto-Valle, Christian W. Schulz, Stefan Netzband, Alessandro Bianchini, Francesco Papi, Stefano Cioni, Pau Trubat, Daniel Alarcon, Climent Molins, Marion Cormier, Konstantin Brüker, Thorsten Lutz, Qing Xiao, Zhongsheng Deng, Florence Haudin, and Akhilesh Goveas
Wind Energ. Sci., 8, 465–485, https://doi.org/10.5194/wes-8-465-2023, https://doi.org/10.5194/wes-8-465-2023, 2023
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This work examines if the motion experienced by an offshore floating wind turbine can significantly affect the rotor performance. It was observed that the system motion results in variations in the load, but these variations are not critical, and the current simulation tools capture the physics properly. Interestingly, variations in the rotor speed or the blade pitch angle can have a larger impact than the system motion itself.
Mac Gaunaa, Niels Troldborg, and Emmanuel Branlard
Wind Energ. Sci., 8, 503–513, https://doi.org/10.5194/wes-8-503-2023, https://doi.org/10.5194/wes-8-503-2023, 2023
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We present an analytical vortex model. Despite its simplicity, the model is fully consistent with 1D momentum theory. It shows that the flow through a non-uniformly loaded rotor operating in non-uniform inflow behaves locally as predicted by 1D momentum theory. As a consequence, the local power coefficient (based on local inflow) of an ideal rotor is unaltered by the presence of shear. Finally, the model shows that there is no cross-shear deflection of the wake of a rotor in sheared inflow.
Kelsey Shaler, Benjamin Anderson, Luis A. Martínez-Tossas, Emmanuel Branlard, and Nick Johnson
Wind Energ. Sci., 8, 383–399, https://doi.org/10.5194/wes-8-383-2023, https://doi.org/10.5194/wes-8-383-2023, 2023
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Free-vortex wake (OLAF) and low-fidelity blade-element momentum (BEM) structural results are compared to high-fidelity simulation results for a flexible downwind turbine for varying inflow conditions. Overall, OLAF results were more consistent than BEM results when compared to SOWFA results under challenging inflow conditions. Differences between OLAF and BEM results were dominated by yaw misalignment angle, with varying shear exponent and turbulence intensity causing more subtle differences.
Francesco Caccia and Alberto Guardone
Wind Energ. Sci., 8, 341–362, https://doi.org/10.5194/wes-8-341-2023, https://doi.org/10.5194/wes-8-341-2023, 2023
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Ice roughness deteriorates wind turbine aerodynamics. We have shown numerically that this also occurs when complex ice shapes are present on the leading edge, as long as the blade's wet region extends beyond the ice shape itself and roughness elements are high enough. Such features are typical of icing events on wind turbines but are not captured by current icing simulation tools. Future research should focus on correctly computing both the wet region of the blade and the roughness height.
Koen Boorsma, Gerard Schepers, Helge Aagard Madsen, Georg Pirrung, Niels Sørensen, Galih Bangga, Manfred Imiela, Christian Grinderslev, Alexander Meyer Forsting, Wen Zhong Shen, Alessandro Croce, Stefano Cacciola, Alois Peter Schaffarczyk, Brandon Lobo, Frederic Blondel, Philippe Gilbert, Ronan Boisard, Leo Höning, Luca Greco, Claudio Testa, Emmanuel Branlard, Jason Jonkman, and Ganesh Vijayakumar
Wind Energ. Sci., 8, 211–230, https://doi.org/10.5194/wes-8-211-2023, https://doi.org/10.5194/wes-8-211-2023, 2023
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Within the framework of the fourth phase of the International Energy Agency's (IEA) Wind Task 29, a large comparison exercise between measurements and aeroelastic simulations has been carried out. Results were obtained from more than 19 simulation tools of various fidelity, originating from 12 institutes and compared to state-of-the-art field measurements. The result is a unique insight into the current status and accuracy of rotor aerodynamic modeling.
Simone Mancini, Koen Boorsma, Gerard Schepers, and Feike Savenije
Wind Energ. Sci., 8, 193–210, https://doi.org/10.5194/wes-8-193-2023, https://doi.org/10.5194/wes-8-193-2023, 2023
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Modern wind turbines are subject to complex wind conditions that are far from the hypothesis of steady uniform inflow at the core of blade element momentum methods (the current industry standard for wind turbine design). Various corrections have been proposed to model this complexity. The present work focuses on modelling the unsteady evolution of wind turbine wakes (dynamic inflow), comparing the different corrections available and highlighting their effects on design load predictions.
Christian Grinderslev, Niels Nørmark Sørensen, Georg Raimund Pirrung, and Sergio González Horcas
Wind Energ. Sci., 7, 2201–2213, https://doi.org/10.5194/wes-7-2201-2022, https://doi.org/10.5194/wes-7-2201-2022, 2022
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As wind turbines increase in size, the risk of flow-induced instabilities increases. This study investigates the phenomenon of vortex-induced vibrations (VIVs) on a large 10 MW wind turbine blade using two high-fidelity methods. It is found that VIVs can occur with multiple equilibrium states for the same flow case, showing an dependence on the initial conditions. This means that a blade which is stable in a flow can become unstable if, e.g., a turbine operation provokes an initial vibration.
Felipe Vittori, José Azcona, Irene Eguinoa, Oscar Pires, Alberto Rodríguez, Álex Morató, Carlos Garrido, and Cian Desmond
Wind Energ. Sci., 7, 2149–2161, https://doi.org/10.5194/wes-7-2149-2022, https://doi.org/10.5194/wes-7-2149-2022, 2022
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This paper describes the results of a wave tank test campaign of a scaled SATH 10 MW INNWIND floating platform. The software-in-the-loop (SiL) hybrid method was used to include the wind turbine thrust and the in-plane rotor moments. Experimental results are compared with a numerical model developed in OpenFAST of the floating wind turbine. The results are discussed, identifying limitations of the numerical models and obtaining conclusions on how to improve them.
Thanasis Barlas, Georg Raimund Pirrung, Néstor Ramos-García, Sergio González Horcas, Ang Li, and Helge Aagaard Madsen
Wind Energ. Sci., 7, 1957–1973, https://doi.org/10.5194/wes-7-1957-2022, https://doi.org/10.5194/wes-7-1957-2022, 2022
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An aeroelastically optimized curved wind turbine blade tip is designed, manufactured, and tested on a novel outdoor rotating rig facility at the Risø campus of the Technical University of Denmark. Detailed aerodynamic measurements for various atmospheric conditions and results are compared to a series of in-house aeroelastic tools with a range of fidelities in aerodynamic modeling. The comparison highlights details in the ability of the codes to predict the performance of such a curved tip.
Jan-Philipp Küppers and Tamara Reinicke
Wind Energ. Sci., 7, 1889–1903, https://doi.org/10.5194/wes-7-1889-2022, https://doi.org/10.5194/wes-7-1889-2022, 2022
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Airfoils play a major role in the technical harnessing of energy from currents such as wind and water. When the angle of attack of a wing changes dynamically, the forces on the wing often change more than would have been assumed from static measurements alone. Since these dynamic forces have a strong influence, e.g., on the performance of airplanes and wind turbines, a neural-network-based model was created that can predict these loads and their stochastic fluctuations.
Thomas Potentier, Emmanuel Guilmineau, Arthur Finez, Colin Le Bourdat, and Caroline Braud
Wind Energ. Sci., 7, 1771–1790, https://doi.org/10.5194/wes-7-1771-2022, https://doi.org/10.5194/wes-7-1771-2022, 2022
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A wind turbine blade equipped with root spoilers is analysed using time domain aeroelastic simulations to assess the impact of passive devices on the turbine AEP and lifetime. A novel way to account for aerofoil-generated unsteadiness in the fatigue calculation is proposed and detailed. The outcome shows that spoilers, on average, can increase the AEP of the turbine. However, the structural impacts on the turbine can be severe if not accounted for initially in the turbine design.
Alessandro Fontanella, Alan Facchinetti, Simone Di Carlo, and Marco Belloli
Wind Energ. Sci., 7, 1711–1729, https://doi.org/10.5194/wes-7-1711-2022, https://doi.org/10.5194/wes-7-1711-2022, 2022
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The aerodynamics of floating wind turbines is complicated by large motions permitted by the foundation. The interaction between turbine, wind, and wake is not yet fully understood. The wind tunnel experiments of this paper shed light on the aerodynamic force and wake response of the floating IEA 15 MW turbine subjected to platform motion as would occur during normal operation. This will help future research on turbine and wind farm control.
Emmanouil M. Nanos, Carlo L. Bottasso, Simone Tamaro, Dimitris I. Manolas, and Vasilis A. Riziotis
Wind Energ. Sci., 7, 1641–1660, https://doi.org/10.5194/wes-7-1641-2022, https://doi.org/10.5194/wes-7-1641-2022, 2022
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A novel way of wind farm control is presented where the wake is deflected vertically to reduce interactions with downstream turbines. This is achieved by moving ballast in a floating offshore platform in order to pitch the support structure and thereby tilt the wind turbine rotor disk. The study considers the effects of this new form of wake control on the aerodynamics of the steering and wake-affected turbines, on the structure, and on the ballast motion system.
Giorgia Guma, Philipp Bucher, Patrick Letzgus, Thorsten Lutz, and Roland Wüchner
Wind Energ. Sci., 7, 1421–1439, https://doi.org/10.5194/wes-7-1421-2022, https://doi.org/10.5194/wes-7-1421-2022, 2022
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Wind turbine aeroelasticity is becoming more and more important because turbine sizes are increasingly leading to more slender blades. On the other hand, complex terrains are of interest because they are far away from urban areas. These regions are characterized by low velocities and high turbulence and are mostly influenced by the presence of forest, and that is why it is necessary to develop high-fidelity tools to correctly simulate the wind turbine's response.
Sarah Barber, Julien Deparday, Yuriy Marykovskiy, Eleni Chatzi, Imad Abdallah, Gregory Duthé, Michele Magno, Tommaso Polonelli, Raphael Fischer, and Hanna Müller
Wind Energ. Sci., 7, 1383–1398, https://doi.org/10.5194/wes-7-1383-2022, https://doi.org/10.5194/wes-7-1383-2022, 2022
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Aerodynamic and acoustic field measurements on operating large-scale wind turbines are key for the further reduction in the costs of wind energy. In this work, a novel cost-effective MEMS (micro-electromechanical systems)-based aerodynamic and acoustic wireless measurement system that is thin, non-intrusive, easy to install, low power and self-sustaining is designed and tested.
Ang Li, Mac Gaunaa, Georg Raimund Pirrung, Alexander Meyer Forsting, and Sergio González Horcas
Wind Energ. Sci., 7, 1341–1365, https://doi.org/10.5194/wes-7-1341-2022, https://doi.org/10.5194/wes-7-1341-2022, 2022
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A consistent method of using two-dimensional airfoil data when using generalized lifting-line methods for the aerodynamic load calculation of non-planar horizontal-axis wind turbines is described. The important conclusions from the unsteady two-dimensional airfoil aerodynamics are highlighted. The impact of using a simplified approach instead of using the full model on the prediction of the aerodynamic performance of non-planar rotors is shown numerically for different aerodynamic models.
Cited articles
Berger, F., Kröger, L., Onnen, D., Petrović, V., and Kühn, M.: Scaled wind turbine setup in a turbulent wind tunnel, J. Phys.: Conf. Ser., 1104, 012026, https://doi.org/10.1088/1742-6596/1104/1/012026, 2018. a
Berger, F., Onnen, D., Schepers, G., and Kühn, M.: Dataset – Radially
resolved dynamic inflow pitch step experiment in wind tunnel, Zenodo [data
set], https://doi.org/10.5281/zenodo.5552171, 2021b. a
Berger, F., Neuhaus, L., Onnen, D., Hölling, M., Schepers, G., and
Kühn, M.: Dataset – Experimental analysis of the dynamic inflow
effect due to coherent gusts, Zenodo [data set], https://doi.org/10.5281/zenodo.7007934, 2022. a
Boorsma, K., Wenz, F., Lindenburg, K., Aman, M., and Kloosterman, M.:
Validation and accommodation of vortex wake codes for wind turbine design
load calculations, Wind Energ. Sci., 5, 699–719,
https://doi.org/10.5194/wes-5-699-2020, 2020. a, b
Buhl, M. L. J.: A New Empirical Relationship between Thrust Coefficient and
Induction Factor for the Turbulent Windmill State, Tech. Rep. NREL/TP-500-36834, National Renewable Energy Laboratory, Golden, https://www.nrel.gov/docs/fy05osti/36834.pdf (last access: 6 January 2022), 2005. a
Drela, M.: An Analysis and Design System for Low Reynolds Number Airfoils,
in: Low Reynolds Number Aerodynamics, vol. 54 of Lecture Notes in Engineering, Springer, Berlin, Heidelberg, 1–12, https://doi.org/10.1007/978-3-642-84010-4, 1989. a
Herráez, I., Daniele, E., and Schepers, J. G.: Extraction of the wake
induction and angle of attack on rotating wind turbine blades from PIV and
CFD results, Wind Energ. Sci., 3, 1–9, https://doi.org/10.5194/wes-3-1-2018, 2018. a, b, c, d
Jonkman, J., Butterfield, S., Musial, W., and Scott, G.: Definition of a 5-MW
Reference Wind Turbine for Offshore System Development, Tech. Rep. NREL/TP-500-38060, NREL – National Renewable Energy Laboratory, Golden, https://www.nrel.gov/docs/fy09osti/38060.pdf (last access: 6 January 2022), 2009. a
Kröger, L., Frederik, J., Van Wingerden, J. W., Peinke, J., and Hölling, M.: Generation of user defined turbulent inflow conditions by an active grid for validation experiments, J. Phys.: Conf. Ser., 1037, 052002, https://doi.org/10.1088/1742-6596/1037/5/052002, 2018. a, b, c
Madsen, H. A., Larsen, T. J., Pirrung, G. R., Li, A., and Zahle, F.:
Implementation of the blade element momentum model on a polar grid and its
aeroelastic load impact, Wind Energ. Sci., 5, 1–27,
https://doi.org/10.5194/wes-5-1-2020, 2020. a, b, c
Marten, D., Lennie, M., Pechlivanoglou, G., Nayeri, C. N., and Paschereit, C. O.: Implementation, Optimization, and Validation of a Nonlinear Lifting
Line-Free Vortex Wake Module Within the Wind Turbine Simulation Code qblade, J. Eng. Gas Turb. Power, 138, 072601, https://doi.org/10.1115/1.4031872, 2016. a
Medici, D., Ivanell, S., Dahlberg, J., and Alfredsson, P.: The upstream flow
of a wind turbine: blockage effect, Wind Energy, 14, 691–697,
https://doi.org/10.1002/we.451, 2011. a
Neuhaus, L., Berger, F., Peinke, J., and Hölling, M.: Exploring the
capabilities of active grids, Exp. Fluids, 62, 130, https://doi.org/10.1007/s00348-021-03224-5, 2021. a, b, c
Øye, S.: Unsteady wake effects caused by pitch-angle changes, in:
Proceedings of the First IEA Symposium on the aerodynamic of wind turbines, London, UK, 15 October 1986, 58–74, 1986. a
Øye, S.: A simple vortex model of a turbine rotor, in: Proceedings of the
Third IEA Symposium on the Aerodynamics of Wind Turbines,
Harwell, UK, 16–17 November 1989, 1–15, 1990. a
Perez-Becker, S., Papi, F., Saverin, J., Marten, D., Bianchini, A., and
Paschereit, C. O.: Is the Blade Element Momentum theory overestimating wind
turbine loads? – An aeroelastic comparison between OpenFAST's AeroDyn and
QBlade's Lifting-Line Free Vortex Wake method, Wind Energ. Sci., 5, 721–743, https://doi.org/10.5194/wes-5-721-2020, 2020.
a
Peters, D. A.: How Dynamic Inflow Survives in the Competitive World of
Rotorcraft Aerodynamics, J. Am. Helicopt. Soc., 54, 11001, https://doi.org/10.4050/JAHS.54.011001, 2009. a
Pirrung, G. R. and Madsen, H. A.: Dynamic inflow effects in measurements and
high-fidelity computations, Wind Energ. Sci., 3, 545–551,
https://doi.org/10.5194/wes-3-545-2018, 2018. a
QBlade: QBlade [software], https://sourceforge.net/projects/qblade, last access: 30 September 2021. a
Shen, W. Z., Mikkelsen, R., Sørensen, J. N., and Bak, C.: Tip loss corrections for wind turbine computations, Wind Energy, 8, 457–475,
https://doi.org/10.1002/we.153, 2005. a
Shirzadeh, K., Hangan, H., Crawford, C., and Hashemi Tari, P.: Investigating
the loads and performance of a model horizontal axis wind turbine under
reproducible IEC extreme operational conditions, Wind Energ. Sci., 6, 477–489, https://doi.org/10.5194/wes-6-477-2021, 2021. a
Snel, H. and Schepers, J.: Joint investigation of dynamic inflow effects and
implementation of an engineering method, Tech. Rep. ECN-C-94-107, Energy
research Center of the Netherlands, Petten, https://publications.ecn.nl/ECN-C--94-107 (last access: 6 January 2022), 1994. a, b, c, d, e, f, g, h, i, j, k, l, m, n
Snel, H., Houwink, R., Bosschers, J., Piers, W. J., van Bussel, G., and
Bruining, A.: Sectional prediction of 3-D effects for stalled flow on
rotating blades and comparison with measurements, Tech. Rep. ECN-RX-93-028,
Energy research Center of the Netherlands, Petten, https://publications.ecn.nl/ECN-RX--93-028 (last access: 6 January 2022), 1993. a
Van Garrel, A.: Development of a Wind Turbine Aerodynamics Simulation
Module, Tech. Rep. ECN-C-03-079, Energy research Center of the Netherlands,
Petten, https://publications.ecn.nl/WIN/2003/ECN-C--03-079 (last access: 6 January 2022), 2003. a
Yu, W., Hong, V., Ferreira, C., and Van Kuik, G. A. M.: Validation of engineering dynamic inflow models by experimental and numerical approaches, J. Phys.: Conf. Ser., 753, 022024, https://doi.org/10.1088/1742-6596/753/2/022024, 2016. a
Yu, W., Tavernier, D., Ferreira, C., van Kuik, G. A., and Schepers, G.: New
dynamic-inflow engineering models based on linear and nonlinear actuator disc
vortex models, Wind Energy, 22, 1433–1450, https://doi.org/10.1002/we.2380, 2019. a, b
Short summary
We proof the dynamic inflow effect due to gusts in wind tunnel experiments with MoWiTO 1.8 in the large wind tunnel of ForWind – University of Oldenburg, where we created coherent gusts with an active grid. The effect is isolated in loads and rotor flow by comparison of a quasi-steady and a dynamic case. The observed effect is not caught by common dynamic inflow engineering models. An improvement to the Øye dynamic inflow model is proposed, matching experiment and corresponding FVWM simulations.
We proof the dynamic inflow effect due to gusts in wind tunnel experiments with MoWiTO 1.8 in...
