Articles | Volume 5, issue 4
https://doi.org/10.5194/wes-5-1487-2020
© Author(s) 2020. 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-5-1487-2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
05 Nov 2020
Research article |
| 05 Nov 2020
| 05 Nov 2020
Laminar-turbulent transition characteristics of a 3-D wind turbine rotor blade based on experiments and computations
DTU Wind Energy, Technical University of Denmark, Aerodynamic Design, Frederiksborgvej 399, 4000 Roskilde, Denmark
Helge Aagaard Madsen
DTU Wind Energy, Technical University of Denmark, Aerodynamic Design, Frederiksborgvej 399, 4000 Roskilde, Denmark
Niels Nørmark Sørensen
DTU Wind Energy, Technical University of Denmark, Aerodynamic Design, Frederiksborgvej 399, 4000 Roskilde, Denmark
Jens Nørkær Sørensen
DTU Wind Energy, Fluid Mechanics, 2800 Lyngby, Denmark
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Mads H. Aa. Madsen, Frederik Zahle, Niels N. Sørensen, and Joaquim R. R. A. Martins
Wind Energ. Sci., 4, 163–192, https://doi.org/10.5194/wes-4-163-2019, https://doi.org/10.5194/wes-4-163-2019, 2019
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Georg Raimund Pirrung and Helge Aagaard Madsen
Wind Energ. Sci., 3, 545–551, https://doi.org/10.5194/wes-3-545-2018, https://doi.org/10.5194/wes-3-545-2018, 2018
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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Preprint withdrawn
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Michael K. McWilliam, Thanasis K. Barlas, Helge A. Madsen, and Frederik Zahle
Wind Energ. Sci., 3, 231–241, https://doi.org/10.5194/wes-3-231-2018, https://doi.org/10.5194/wes-3-231-2018, 2018
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Mads Mølgaard Pedersen, Torben Juul Larsen, Helge Aagaard Madsen, and Søren Juhl Andersen
Wind Energ. Sci., 3, 121–138, https://doi.org/10.5194/wes-3-121-2018, https://doi.org/10.5194/wes-3-121-2018, 2018
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The wind speed measured by a flow sensor mounted on the blade of a wind turbine is disturbed by the turbine. This paper presents a method to obtain the free turbulence inflow by compensating for this disturbance.
The method is tested using numerical simulations and can be used to extract inflow information for accurate aeroelastic load simulations.
Georg R. Pirrung, Helge A. Madsen, and Scott Schreck
Wind Energ. Sci., 2, 521–532, https://doi.org/10.5194/wes-2-521-2017, https://doi.org/10.5194/wes-2-521-2017, 2017
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Current fast aeroelastic wind turbine codes suitable for certification lack an induction model for standstill conditions. A near-wake model for wind turbines in operation is extended to cover these conditions. The model is validated in aerodynamic simulations of the NREL/NASA Ames Phase VI rotor. Good agreement with the experiments has been obtained in attached flow and beginning separation. Aeroelastic simulations of the DTU 10 MW turbine in standstill indicate a minor impact of the model.
Mads M. Pedersen, Torben J. Larsen, Helge Aa. Madsen, and Gunner Chr. Larsen
Wind Energ. Sci., 2, 547–567, https://doi.org/10.5194/wes-2-547-2017, https://doi.org/10.5194/wes-2-547-2017, 2017
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This paper presents an alternative method to evaluate power performance and loads on wind turbines using a blade-mounted flow sensor. A high correlation is found between the wind speed measured at the blades and the power/loads, and simulations indicate that it is possible to reduce the time required for power and load assessment considerably. This result, however, cannot be confirmed from the full-scale measurement study due to practical circumstances.
Maarten Paul van der Laan and Niels Nørmark Sørensen
Wind Energ. Sci., 2, 285–294, https://doi.org/10.5194/wes-2-285-2017, https://doi.org/10.5194/wes-2-285-2017, 2017
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Georg Pirrung, Vasilis Riziotis, Helge Madsen, Morten Hansen, and Taeseong Kim
Wind Energ. Sci., 2, 15–33, https://doi.org/10.5194/wes-2-15-2017, https://doi.org/10.5194/wes-2-15-2017, 2017
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The certification process of a wind turbine requires simulations of a coupled structural and aerodynamic wind turbine model in many different external conditions. Due to the large number of load cases, the complexity of the aerodynamics models has to be limited. In this paper, a simplified vortex method based aerodynamics model is described. It is shown that this model, which is fast enough for use in a certification context, can produce results similar to those of a more complex vortex model.
Dalibor Cavar, Pierre-Elouan Réthoré, Andreas Bechmann, Niels N. Sørensen, Benjamin Martinez, Frederik Zahle, Jacob Berg, and Mark C. Kelly
Wind Energ. Sci., 1, 55–70, https://doi.org/10.5194/wes-1-55-2016, https://doi.org/10.5194/wes-1-55-2016, 2016
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Feasibility of a freely available CFD tool, OpenFOAM, in calculating flows of general relevance to the wind industry is investigated by comparing several aspects of its performance to a well-established in-house EllipSys3D solver. The comparison is focused on CFD solver demands regarding grid generation process and computational time.
The quality and accuracy of the achieved results are investigated by conducting the computations using identical/similar solver parameters and numerical setups..
G. A. M. van Kuik, J. Peinke, R. Nijssen, D. Lekou, J. Mann, J. N. Sørensen, C. Ferreira, J. W. van Wingerden, D. Schlipf, P. Gebraad, H. Polinder, A. Abrahamsen, G. J. W. van Bussel, J. D. Sørensen, P. Tavner, C. L. Bottasso, M. Muskulus, D. Matha, H. J. Lindeboom, S. Degraer, O. Kramer, S. Lehnhoff, M. Sonnenschein, P. E. Sørensen, R. W. Künneke, P. E. Morthorst, and K. Skytte
Wind Energ. Sci., 1, 1–39, https://doi.org/10.5194/wes-1-1-2016, https://doi.org/10.5194/wes-1-1-2016, 2016
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This work introduces the FLOW Estimation and Rose Superposition (FLOWERS) wind turbine wake model. This model analytically integrates the wake over wind directions to provide a time-averaged flow field. This new formulation is used to perform layout optimization. The FLOWERS model provides a smooth flow field over an entire wind plant at fraction of the computational cost of the standard numerical integration approach.
Antoine Soulier, Caroline Braud, Dimitri Voisin, and Frédéric Danbon
Wind Energ. Sci., 7, 1043–1052, https://doi.org/10.5194/wes-7-1043-2022, https://doi.org/10.5194/wes-7-1043-2022, 2022
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The e-TellTale, a new aerodynamic sensor, has been tested in a large wind tunnel at CSTB. This sensor has been designed to detect the flow separation on wind turbine blades, which can cause energy production losses and increased aging of the blades. These wind tunnel tests highlighted the good ability of the e-TellTale to detect the flow separation and the influence of the size and location of the e-TellTale on the flow separation detection.
Jörg Alber, Marinos Manolesos, Guido Weinzierl-Dlugosch, Johannes Fischer, Alexander Schönmeier, Christian Navid Nayeri, Christian Oliver Paschereit, Joachim Twele, Jens Fortmann, Pier Francesco Melani, and Alessandro Bianchini
Wind Energ. Sci., 7, 943–965, https://doi.org/10.5194/wes-7-943-2022, https://doi.org/10.5194/wes-7-943-2022, 2022
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This paper investigates the potentials and the limitations of mini Gurney flaps and their combination with vortex generators for improved rotor blade performance of wind turbines. These small passive add-ons are installed in order to increase the annual energy production by mitigating the effects of both early separation toward the root region and surface erosion toward the tip region of the blade. As such, this study contributes to the reliable and long-term generation of renewable energy.
Mohammad Sadman Sakib and D. Todd Griffith
Wind Energ. Sci., 7, 677–696, https://doi.org/10.5194/wes-7-677-2022, https://doi.org/10.5194/wes-7-677-2022, 2022
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This paper presents a comprehensive aerodynamic design study for a 5 MW Darrieus offshore VAWT in the context of multi-megawatt floating VAWTs. This study systematically analyzes the effect of different, important design variables including the number of blades, aspect ratio and blade chord tapering in a comprehensive load analysis of both the parked and operating aerodynamic loads including turbine power performance analysis using a vortex-based aerodynamic model.
Thomas Potentier, Emmanuel Guilmineau, Arthur Finez, Colin Le Bourdat, and Caroline Braud
Wind Energ. Sci., 7, 647–657, https://doi.org/10.5194/wes-7-647-2022, https://doi.org/10.5194/wes-7-647-2022, 2022
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The spoiler is found to efficiently rearrange the mean flow seen by thick aerofoil: adding lift throughout the positive angles of attack, the drawback is a high drag penalty coupled with high unsteadiness of the aerodynamic forces. The impact of this type of excitation will be quantified further in terms of energy production and fatigue in future work.
Yong Su Jung, Ganesh Vijayakumar, Shreyas Ananthan, and James Baeder
Wind Energ. Sci., 7, 603–622, https://doi.org/10.5194/wes-7-603-2022, https://doi.org/10.5194/wes-7-603-2022, 2022
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In RANS CFD, the eN-based method showed its superiority over local correlation-based transition models (LCTMs) coupled with the SST turbulence model for predicting transition behavior at high-Reynolds-number flows (3–15 million). We evaluated the performance of two LCTMs coupled with the SA turbulence model. As a result, the SA-based two-equation transition model showed a comparable performance with the eN-based method and better glide ratio (L/D) predictions than the SST-based model.
Rodrigo Soto-Valle, Stefano Cioni, Sirko Bartholomay, Marinos Manolesos, Christian Navid Nayeri, Alessandro Bianchini, and Christian Oliver Paschereit
Wind Energ. Sci., 7, 585–602, https://doi.org/10.5194/wes-7-585-2022, https://doi.org/10.5194/wes-7-585-2022, 2022
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This paper compares different vortex identification methods to evaluate their suitability to study the tip vortices of a wind turbine. The assessment is done through experimental data from the wake of a wind turbine model. Results show comparability in some aspects as well as significant differences, providing evidence to justify further comparisons. Therefore, this study proves that the selection of the most suitable postprocessing methods of tip vortex data is pivotal to ensure robust results.
Axelle Viré, Bruce LeBlanc, Julia Steiner, and Nando Timmer
Wind Energ. Sci., 7, 573–584, https://doi.org/10.5194/wes-7-573-2022, https://doi.org/10.5194/wes-7-573-2022, 2022
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There is continuous effort to try and improve the aerodynamic performance of wind turbine blades. This work shows that adding a leading-edge slat to wind turbine blades can significantly enhance the aerodynamic performance of wind turbines, even more than with vortex generators (which are commonly used on commercial turbines). The findings are obtained through wind tunnel tests on different airfoil–slat combinations.
Carlos Ferreira, Wei Yu, Arianna Sala, and Axelle Viré
Wind Energ. Sci., 7, 469–485, https://doi.org/10.5194/wes-7-469-2022, https://doi.org/10.5194/wes-7-469-2022, 2022
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Floating offshore wind turbines may experience large surge motions that, when faster than the local wind speed, cause rotor–wake interaction.
We derive a model which is able to predict the wind speed at the wind turbine, even for large and fast motions and load variations in the wind turbine.
The proposed dynamic inflow model includes an adaptation for highly loaded flow, and it is accurate and simple enough to be easily implemented in most blade element momentum design models.
Emmanuel Branlard, Ian Brownstein, Benjamin Strom, Jason Jonkman, Scott Dana, and Edward Ian Baring-Gould
Wind Energ. Sci., 7, 455–467, https://doi.org/10.5194/wes-7-455-2022, https://doi.org/10.5194/wes-7-455-2022, 2022
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In this work, we present an aerodynamic tool that can model an arbitrary collections of wings, blades, rotors, and towers. With these functionalities, the tool can be used to study and design advanced wind energy concepts, such as horizontal-axis wind turbines, vertical-axis wind turbines, kites, or multi-rotors. This article describes the key features of the tool and presents multiple applications. Field measurements of horizontal- and vertical-axis wind turbines are used for comparison.
Ang Li, Georg Raimund Pirrung, Mac Gaunaa, Helge Aagaard Madsen, and Sergio González Horcas
Wind Energ. Sci., 7, 129–160, https://doi.org/10.5194/wes-7-129-2022, https://doi.org/10.5194/wes-7-129-2022, 2022
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An engineering aerodynamic model for the swept horizontal-axis wind turbine blades is proposed. It uses a combination of analytical results and engineering approximations. The performance of the model is comparable with heavier high-fidelity models but has similarly low computational cost as currently used low-fidelity models. The model could be used for an efficient and accurate load calculation of swept wind turbine blades and could eventually be integrated in a design optimization framework.
Ang Li, Mac Gaunaa, Georg Raimund Pirrung, and Sergio González Horcas
Wind Energ. Sci., 7, 75–104, https://doi.org/10.5194/wes-7-75-2022, https://doi.org/10.5194/wes-7-75-2022, 2022
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An engineering aerodynamic model for non-planar horizontal-axis wind turbines is proposed. The performance of the model is comparable with high-fidelity models but has similarly low computational cost as currently used low-fidelity models, which do not have the capability to model non-planar rotors. The developed model could be used for an efficient and accurate load calculation of non-planar wind turbines and eventually be integrated in a design optimization framework.
David H. Wood and Eric J. Limacher
Wind Energ. Sci., 6, 1413–1425, https://doi.org/10.5194/wes-6-1413-2021, https://doi.org/10.5194/wes-6-1413-2021, 2021
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The airflow through a wind turbine must expand as it goes through the blades for them to extract energy from the wind. Expansion has not been properly incorporated in wind turbine aerodynamics. We show that the conventional equation for wind turbine thrust becomes inaccurate when the expansion is maximized to achieve maximum power, and expansion reduces power by around 6 %. We formulate equations for the disturbance of the external flow and show that this is maximized at the rotor plane.
Frederik Berger, David Onnen, Gerard Schepers, and Martin Kühn
Wind Energ. Sci., 6, 1341–1361, https://doi.org/10.5194/wes-6-1341-2021, https://doi.org/10.5194/wes-6-1341-2021, 2021
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Dynamic inflow denotes the unsteady aerodynamic response to fast changes in rotor loading and leads to load overshoots. We performed a pitch step experiment with MoWiTO 1.8 in the large wind tunnel of ForWind – University of Oldenburg. We measured axial and tangential inductions with a recent method with a 2D-LDA system and performed load and wake measurements. These radius-resolved measurements allow for new insights into the dynamic inflow phenomenon.
Thanasis Barlas, Georg Raimund Pirrung, Néstor Ramos-García, Sergio González Horcas, Robert Flemming Mikkelsen, Anders Smærup Olsen, and Mac Gaunaa
Wind Energ. Sci., 6, 1311–1324, https://doi.org/10.5194/wes-6-1311-2021, https://doi.org/10.5194/wes-6-1311-2021, 2021
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Curved blade tips can potentially have a significant impact on wind turbine performance and loads. A swept tip shape optimized for wind turbine applications is tested in a wind tunnel. A range of numerical aerodynamic simulation tools with various levels of fidelity are compared. We show that all numerical tools except for the simplest blade element momentum based are in good agreement with the measurements, suggesting the required level of model fidelity necessary for the design of such tips.
Vinit Dighe, Dhruv Suri, Francesco Avallone, and Gerard van Bussel
Wind Energ. Sci., 6, 1263–1275, https://doi.org/10.5194/wes-6-1263-2021, https://doi.org/10.5194/wes-6-1263-2021, 2021
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Ducted wind turbines (DWTs) can be used for energy harvesting in urban areas where non-uniform flows are caused by the presence of buildings or other surface discontinuities. For this reason, the aerodynamic performance of DWTs in yawed-flow conditions must be characterized. It is found that the duct cross-section camber offers not only insensitivity to yaw but also a gain in performance up to a specific yaw angle; thereafter any further increase in yaw results in a performance drop.
Alessandro Fontanella, Ilmas Bayati, Robert Mikkelsen, Marco Belloli, and Alberto Zasso
Wind Energ. Sci., 6, 1169–1190, https://doi.org/10.5194/wes-6-1169-2021, https://doi.org/10.5194/wes-6-1169-2021, 2021
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The scale model wind tunnel experiment presented in this paper investigated the aerodynamic response of a floating turbine subjected to imposed surge motion. The problem is studied under different aspects, from airfoil aerodynamics to wake, in a coherent manner. Results show quasi-static behavior for reduced frequencies lower than 0.5 and possible unsteadiness for higher surge motion frequencies. Data are made available to the public for future verification and calibration of numerical models.
Edgar Martinez-Ojeda, Francisco Javier Solorio Ordaz, and Mihir Sen
Wind Energ. Sci., 6, 1061–1077, https://doi.org/10.5194/wes-6-1061-2021, https://doi.org/10.5194/wes-6-1061-2021, 2021
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A model for computing vertical-axis wind turbine farms was developed using computational fluid dynamics open-source software. This model has the potential of evaluating wind farm configurations which can lead to a higher annual energy yield. Such configurations have not been studied thoroughly due to the fact that most analysis tools are computationally expensive. This model can also be run in personal computers within a matter of minutes or hours depending on the number of turbines.
Nojan Bagheri-Sadeghi, Brian T. Helenbrook, and Kenneth D. Visser
Wind Energ. Sci., 6, 1031–1041, https://doi.org/10.5194/wes-6-1031-2021, https://doi.org/10.5194/wes-6-1031-2021, 2021
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The design of a ducted wind turbine was optimized to maximize the power per total cross-sectional area of the device. The associated power coefficient was 0.70, which is significantly greater than that obtainable from an open rotor turbine. Furthermore, it was shown that there is an optimal duct length, which is 15 % of the rotor diameter.
Chengyu Wang, Filippo Campagnolo, Helena Canet, Daniel J. Barreiro, and Carlo L. Bottasso
Wind Energ. Sci., 6, 961–981, https://doi.org/10.5194/wes-6-961-2021, https://doi.org/10.5194/wes-6-961-2021, 2021
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This paper quantifies the fidelity of the wakes generated by a small (1 m diameter) scaled wind turbine model operated in a large boundary layer wind tunnel. A detailed scaling analysis accompanied by large-eddy simulations shows that these wakes are very realistic scaled versions of the ones generated by the parent full-scale wind turbine in the field.
Mohammad Youssef Mahfouz, Climent Molins, Pau Trubat, Sergio Hernández, Fernando Vigara, Antonio Pegalajar-Jurado, Henrik Bredmose, and Mohammad Salari
Wind Energ. Sci., 6, 867–883, https://doi.org/10.5194/wes-6-867-2021, https://doi.org/10.5194/wes-6-867-2021, 2021
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This paper introduces the numerical models of two 15 MW floating offshore wind turbines (FOWTs) WindCrete and Activefloat. WindCrete is a spar floating platform designed by Universitat Politècnica de Catalunya, while Activefloat is a semi-submersible platform designed by Esteyco. The floaters are designed within the Horizon 2020 project COREWIND. Later in the paper, the responses of both models to wind and second-order waves are analysed with an emphasis on the effect of second-order waves.
Thales Fava, Mikaela Lokatt, Niels Sørensen, Frederik Zahle, Ardeshir Hanifi, and Dan Henningson
Wind Energ. Sci., 6, 715–736, https://doi.org/10.5194/wes-6-715-2021, https://doi.org/10.5194/wes-6-715-2021, 2021
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This work develops a simplified framework to predict transition to turbulence on wind-turbine blades. The model is based on the boundary-layer and parabolized stability equations, including rotation and three-dimensionality effects. We show that these effects may promote transition through highly oblique Tollmien–Schlichting (TS) or crossflow modes at low radii, and they should be considered for a correct transition prediction. At high radii, transition tends to occur through 2D TS modes.
Stefano Macrí, Sandrine Aubrun, Annie Leroy, and Nicolas Girard
Wind Energ. Sci., 6, 585–599, https://doi.org/10.5194/wes-6-585-2021, https://doi.org/10.5194/wes-6-585-2021, 2021
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This paper investigates the effect of misaligning a wind turbine on its wake deviation response and on the global load variation of a downstream wind turbine during a positive and negative yaw maneuver, representing a misalignment–realignment scenario. Yaw maneuvers could be used to voluntarily misalign wind turbines when wake steering control is targeted. The aim of this wind farm control strategy is to optimize the overall production of the wind farm and its lifetime.
Luis A. Martínez-Tossas, Jennifer King, Eliot Quon, Christopher J. Bay, Rafael Mudafort, Nicholas Hamilton, Michael F. Howland, and Paul A. Fleming
Wind Energ. Sci., 6, 555–570, https://doi.org/10.5194/wes-6-555-2021, https://doi.org/10.5194/wes-6-555-2021, 2021
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In this paper a three-dimensional steady-state solver for flow through a wind farm is developed and validated. The computational cost of the solver is on the order of seconds for large wind farms. The model is validated using high-fidelity simulations and SCADA.
Thanasis Barlas, Néstor Ramos-García, Georg Raimund Pirrung, and Sergio González Horcas
Wind Energ. Sci., 6, 491–504, https://doi.org/10.5194/wes-6-491-2021, https://doi.org/10.5194/wes-6-491-2021, 2021
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A method to design advanced tip extensions for modern wind turbine blades is presented in this work. The resulting design concept has high potential in terms of actual implementation in a real rotor upscaling with a potential business case in reducing the cost of energy produced by future large wind turbine rotors.
Antoine Soulier, Caroline Braud, Dimitri Voisin, and Bérengère Podvin
Wind Energ. Sci., 6, 409–426, https://doi.org/10.5194/wes-6-409-2021, https://doi.org/10.5194/wes-6-409-2021, 2021
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Monitoring the flow features over wind turbine blades is a challenging task that has become more and more crucial to monitor and/or operate wind turbine blades. This paper demonstrates the ability of an innovative sensor to detect these features over wind turbine blades. The spatiotemporal description of the flow over the surface has been measured over an oscillating blade section and the strip displacement was compared, showing the ability of the sensor to detect stall.
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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This paper presents two methods on how to estimate the lift force that is created by a wing. These methods were experimentally assessed in a wind tunnel. Furthermore, an active trailing-edge flap, as seen on airplanes for example, is used to alleviate fluctuating loads that are created within the employed wind tunnel. Thereby, an active flow control device that can potentially serve on wind turbines to lower fatigue or lower the material used for the blades is examined.
Eric J. Limacher and David H. Wood
Wind Energ. Sci., 6, 191–201, https://doi.org/10.5194/wes-6-191-2021, https://doi.org/10.5194/wes-6-191-2021, 2021
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This paper describes a new analysis of wind turbine thrust based on removing pressure from the equations for the wind flow through a wind turbine rotor. We show that the equation is free from the effects of flow expansion that must accompany the slowing down of the wind through the blades as they extract the kinetic energy. The conditions under which the assumptions are used in blade-element analysis, which is fundamental for wind turbine aerodynamics, are made clear for the first time.
Alejandro Gomez Gonzalez, Peder B. Enevoldsen, Athanasios Barlas, and Helge A. Madsen
Wind Energ. Sci., 6, 33–43, https://doi.org/10.5194/wes-6-33-2021, https://doi.org/10.5194/wes-6-33-2021, 2021
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This work describes a series of tests of active flaps on a 4 MW wind turbine. The measurements were performed between October 2017 and June 2019 using two different active flap configurations on a blade of the turbine, showing a potential to manipulate the loading of the turbine between 5 % and 10 %. This project is performed with the aim of demonstrating a technology with the potential of reducing the levelized cost of energy for wind power.
Rodrigo Soto-Valle, Sirko Bartholomay, Jörg Alber, Marinos Manolesos, Christian Navid Nayeri, and Christian Oliver Paschereit
Wind Energ. Sci., 5, 1771–1792, https://doi.org/10.5194/wes-5-1771-2020, https://doi.org/10.5194/wes-5-1771-2020, 2020
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In this paper, a method to determine the angle of attack on a wind turbine rotor blade using a chordwise pressure distribution measurement was applied. The approach used a reduced number of pressure tap data located close to the blade leading edge. The results were compared with the measurements from three external probes mounted on the blade at different radial positions and with analytical calculations.
Jörg Alber, Rodrigo Soto-Valle, Marinos Manolesos, Sirko Bartholomay, Christian Navid Nayeri, Marvin Schönlau, Christian Menzel, Christian Oliver Paschereit, Joachim Twele, and Jens Fortmann
Wind Energ. Sci., 5, 1645–1662, https://doi.org/10.5194/wes-5-1645-2020, https://doi.org/10.5194/wes-5-1645-2020, 2020
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The aerodynamic impact of Gurney flaps is investigated on the rotor blades of the Berlin Research Turbine. The findings of this research project contribute to performance improvements of different-size rotor blades. Gurney flaps are considered a worthwhile passive flow-control device in order to alleviate the adverse effects of both early separation in the inner blade region and leading-edge erosion throughout large parts of the blade span.
Chengyu Wang, Filippo Campagnolo, and Carlo L. Bottasso
Wind Energ. Sci., 5, 1537–1550, https://doi.org/10.5194/wes-5-1537-2020, https://doi.org/10.5194/wes-5-1537-2020, 2020
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A new method is described to identify the aerodynamic characteristics of blade airfoils directly from operational data of the turbine. Improving on a previously published approach, the present method is based on a new maximum likelihood formulation that includes errors both in the outputs and the inputs. The method is demonstrated on the identification of the polars of small-scale turbines for wind tunnel testing.
Julia Steiner, Axelle Viré, Francesco Benetti, Nando Timmer, and Richard Dwight
Wind Energ. Sci., 5, 1075–1095, https://doi.org/10.5194/wes-5-1075-2020, https://doi.org/10.5194/wes-5-1075-2020, 2020
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The manuscript deals with the aerodynamic design of slat elements for thick-base airfoils at high Reynolds numbers using integral boundary layer and computational fluid dynamics models. The results highlight aerodynamic benefits such as high stall angle, low roughness sensitivity, and higher aerodynamic efficiency than standard single-element configurations. However, this is accompanied by a steep drop in lift post-stall and potentially issues related to the structural design of the blade.
Galih Bangga, Thorsten Lutz, and Matthias Arnold
Wind Energ. Sci., 5, 1037–1058, https://doi.org/10.5194/wes-5-1037-2020, https://doi.org/10.5194/wes-5-1037-2020, 2020
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Robust and accurate dynamic stall modeling remains one of the most difficult tasks in wind turbine load calculations despite its long research effort in the past. The present paper describes a new
second-order dynamic stall model for wind turbine airfoils. The new model is robust and improves the prediction for the aerodynamic forces and their higher-harmonic effects due to vortex shedding but also provides improved predictions for pitching moment and drag.
George Papadakis and Marinos Manolesos
Wind Energ. Sci., 5, 911–927, https://doi.org/10.5194/wes-5-911-2020, https://doi.org/10.5194/wes-5-911-2020, 2020
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Flatback airfoils are used in the root region of wind turbine blades since they have several structural and aerodynamic benefits. Several flow control devices are incorporated to mitigate the effects of vortex shedding in the wake of such airfoils. In this work, two different numerical approaches are compared to wind tunnel measurements to assess the suitability of each method for predicting the performance of the flow control devices in terms of loads and unsteady characteristics.
Gijs A. M. van Kuik
Wind Energ. Sci., 5, 855–865, https://doi.org/10.5194/wes-5-855-2020, https://doi.org/10.5194/wes-5-855-2020, 2020
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The paper compares actuator discs in propeller and wind turbine mode. At very low rotational speed, propeller discs have an expanding wake while still energy is put into the wake. The velocity at the disc in the plane containing the axis is practically uniform: a few per mille deviation for wind turbine discs and a few per cent for propeller discs. The deviations are caused by the different strengths of the singularity in the wake boundary vorticity strength at its leading edge.
Matthew Lennie, Johannes Steenbuck, Bernd R. Noack, and Christian Oliver Paschereit
Wind Energ. Sci., 5, 819–838, https://doi.org/10.5194/wes-5-819-2020, https://doi.org/10.5194/wes-5-819-2020, 2020
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This study presents a marriage of unsteady aerodynamics and machine learning. When airfoils are subjected to high inflow angles, the flow no longer follows the surface and the flow is said to be separated. In this flow regime, the forces experienced by the airfoil are highly unsteady. This study uses a range of machine learning techniques to extract infomation from test data to help us understand the flow regime and makes recomendations on how to model it.
Peter Jamieson
Wind Energ. Sci., 5, 807–818, https://doi.org/10.5194/wes-5-807-2020, https://doi.org/10.5194/wes-5-807-2020, 2020
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Wind turbine rotors are usually designed to maximize power performance, accepting any loading results. However, from the most basic wind turbine theory, actuator disc theory, two other optimization paths are demonstrated, which may lead to more cost-effective technology – the low-induction rotor where an expanded rotor diameter and some extra power is achieved without increasing the blade root bending moment and the secondary rotor which can provide a very low torque and low-cost drivetrain.
Axelle Viré, Adriaan Derksen, Mikko Folkersma, and Kumayl Sarwar
Wind Energ. Sci., 5, 793–806, https://doi.org/10.5194/wes-5-793-2020, https://doi.org/10.5194/wes-5-793-2020, 2020
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Vortex-induced vibrations are structural vibrations that can occur due to the shedding of flow vortices when a fluid flow passes around a structure. Here, conditions specific to wind turbine towers are investigated numerically. The work highlights a complex interplay between structural and fluid dynamics. In particular, certain conditions lead to a continuous alternation between self-exciting and self-limiting vortex-induced vibrations, linked to a change in the sign of the aerodynamic damping.
Koen Boorsma, Florian Wenz, Koert Lindenburg, Mansoor Aman, and Menno Kloosterman
Wind Energ. Sci., 5, 699–719, https://doi.org/10.5194/wes-5-699-2020, https://doi.org/10.5194/wes-5-699-2020, 2020
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The present publication has contributed towards making vortex wake models ready for application to certification load calculations. The reduction in flapwise blade root moment fatigue loading using vortex wake models instead of the blade element momentum method has been verified using dedicated CFD simulations. A validation effort against a long-term field measurement campaign featuring 2.5 MW turbines has confirmed the improved prediction of unsteady load characteristics by vortex wake models.
Johannes Schreiber, Carlo L. Bottasso, Bastian Salbert, and Filippo Campagnolo
Wind Energ. Sci., 5, 647–673, https://doi.org/10.5194/wes-5-647-2020, https://doi.org/10.5194/wes-5-647-2020, 2020
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The paper describes a new method that uses standard historical operational data and reconstructs the flow at the rotor disk of each turbine in a wind farm. The method is based on a baseline wind farm flow and wake model, augmented with error terms that are
learnedfrom operational data using an ad hoc system identification approach. Both wind tunnel experiments and real data from a wind farm at a complex terrain site are used to show the capabilities of the new method.
Henrik Asmuth, Hugo Olivares-Espinosa, and Stefan Ivanell
Wind Energ. Sci., 5, 623–645, https://doi.org/10.5194/wes-5-623-2020, https://doi.org/10.5194/wes-5-623-2020, 2020
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The presented work investigates the potential of the lattice Boltzmann method (LBM) for numerical simulations of wind turbine wakes. The LBM is a rather novel, alternative approach for computational fluid dynamics (CFD) that allows for significantly faster simulations. The study shows that the method provides similar results when compared to classical CFD approaches while only requiring a fraction of the computational demand.
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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It is crucial to model dynamic stall accurately to reduce inaccuracies in predicting fatigue and extreme loads. This paper investigates a new dynamic stall model. Improvements are proposed based on experiments. The updated model shows significant improvements over the initial model; however, further validation and research are still required. This updated model might be incorporated into future wind turbine design codes and will hopefully reduce inaccuracies in predicted wind turbine loads.
Christian Grinderslev, Federico Belloni, Sergio González Horcas, and Niels Nørmark Sørensen
Wind Energ. Sci., 5, 543–560, https://doi.org/10.5194/wes-5-543-2020, https://doi.org/10.5194/wes-5-543-2020, 2020
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This study focuses on coupled computational fluid and structural dynamics simulations of a dynamic structural test of a wind turbine blade, as performed in laboratories. It is found that drag coefficients used for simulations, when planning fatigue tests, underestimate air resistance to the dynamic motion that the blade undergoes during tests. If this is not corrected for, this can result in the forces applied to the blade actually being lower in reality during tests than what was planned.
Alexander R. Meyer Forsting, Georg R. Pirrung, and Néstor Ramos-García
Wind Energ. Sci., 5, 349–353, https://doi.org/10.5194/wes-5-349-2020, https://doi.org/10.5194/wes-5-349-2020, 2020
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Simulations of wind farms allow the estimation of the forces acting on the turbines and thus their lifetime and power production. Representing the actual geometric shape of turbines in a realistic atmospheric flow is computationally expensive; therefore they are modelled in a simplified manner. Unfortunately, these simplifications negatively impact the estimated forces. We developed an open-source aerodynamic model that corrects the forces, giving more accurate estimates of lifetime and power.
Johannes Schreiber, Amr Balbaa, and Carlo L. Bottasso
Wind Energ. Sci., 5, 237–244, https://doi.org/10.5194/wes-5-237-2020, https://doi.org/10.5194/wes-5-237-2020, 2020
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An analytical wake model with a double-Gaussian velocity distribution is used to improve on a similar formulation by Keane et al (2016). The choice of a double-Gaussian shape function is motivated by the behavior of the near-wake region that is observed in numerical simulations and experimental measurements. The model is calibrated and validated using large eddy simulations replicating scaled wind turbine experiments, yielding improved results with respect to a classical single-Gaussian profile.
Miguel Sanchez Gomez and Julie K. Lundquist
Wind Energ. Sci., 5, 125–139, https://doi.org/10.5194/wes-5-125-2020, https://doi.org/10.5194/wes-5-125-2020, 2020
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Wind turbine performance depends on various atmospheric conditions. We quantified the effect of the change in wind direction and speed with height (direction and speed wind shear) on turbine power at a wind farm in Iowa. Turbine performance was affected during large direction shear and small speed shear conditions and favored for the opposite scenarios. These effects make direction shear significant when analyzing the influence of different atmospheric variables on turbine operation.
Helge Aagaard Madsen, Torben Juul Larsen, Georg Raimund Pirrung, Ang Li, and Frederik Zahle
Wind Energ. Sci., 5, 1–27, https://doi.org/10.5194/wes-5-1-2020, https://doi.org/10.5194/wes-5-1-2020, 2020
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We show in the paper that the upscaling of turbines has led to new requirements in simulation of the unsteady aerodynamic forces by the engineering blade element momentum (BEM) model, originally developed for simulation of the aerodynamics of propellers and helicopters. We present a new implementation of the BEM model on a polar grid which can be characterized as an engineering actuator disc model. The aeroelastic load impact of the new BEM implementation is analyzed and quantified.
Maarten Paul van der Laan, Søren Juhl Andersen, and Pierre-Elouan Réthoré
Wind Energ. Sci., 4, 645–651, https://doi.org/10.5194/wes-4-645-2019, https://doi.org/10.5194/wes-4-645-2019, 2019
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Wind farm layouts are designed by simple engineering wake models, which are fast to compute but also include a high uncertainty. Higher-fidelity models, such as Reynolds-averaged Navier–Stokes, can be used to verify optimized wind farm layouts, although the computational costs are high due to the large number of cases that are needed to calculate the annual energy production. This article presents a new wind turbine control method to speed up the high-fidelity simulations by a factor of 2–3.
Freddy J. Madsen, Antonio Pegalajar-Jurado, and Henrik Bredmose
Wind Energ. Sci., 4, 527–547, https://doi.org/10.5194/wes-4-527-2019, https://doi.org/10.5194/wes-4-527-2019, 2019
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This paper presents a comparison study of the simplified model QuLAF (Quick Load Analysis of Floating wind turbines) and FAST for the planar version of various design load cases, in order to investigate how accurate results can be obtained from this simplified model.
The overall analysis shows that QuLAF is generally very good at estimating the bending moment at the tower base and the floater motions, whereas the nacelle acceleration is generally underpredicted.
Cited articles
Abu-Ghannam, B. and Shaw, R.: Natural transition of boundary layers – the
effects of turbulence, pressure gradient, and flow history, J. Mech. Eng. Sci., 22, 213–228, 1980. a
Arnal, D., Gasparian, G., and Salinas, H.: Recent Advances in Theoretical
Methods for Laminar-Turbulent Transition Prediction, in: 36th AIAA Aerospace
Sciences Meeting and Exhibit, 12–15 January 1998, Reno, NV, USA, https://doi.org/10.2514/6.1998-223, 1998. a
Bak, C., Aagaard Madsen, H., Schmidt Paulsen, U., Gaunaa, M., Fuglsang, P.,
Romblad, J., Olesen, N., Enevoldsen, P., Laursen, J., and Jensen, L.:
DAN-AERO MW: Detailed aerodynamic measurements on a full scale MW wind
turbine, in: EWEC 2010 Proceedings online, European Wind Energy Association (EWEA), Warsaw, 2010. a
Bertolotti, F. P., Herbert, T., and Spalart, P. R.: Linear and nonlinear
stability of the Blasius boundary layer, J. Fluid Mech., 242, 441–474, https://doi.org/10.1017/S0022112092002453, 1992. a
Biau, D., Arnal, D., and Vermeersch, O.: A transition prediction model for
boundary layers subjected to free-stream turbulence, Aerospace Sci. Technol., 11, 370–375, 2007. a
Boorsma, K., Schepers, J. G., Gomez-Iradi, S., Herraez, I., Lutz, T., Weihing, P., Oggiano, L., Pirrung, G., Madsen, H. A., Shen, W. Z., and Rahimi, H.: Final report of IEA wind task 29 Mexnext (Phase 3), Wind Energy, available at: https://scholar.google.com.tr/scholar?cluster=6869701785559421965&hl=en&as_sdt=0,5
(last access: October 2020), 2018. a
Chaviaropoulos, P. K., Sieros, G., Prospathopoulos, J. M., Diakakis, K., and
Voutsinas, S. G.: Design and CFD-based Performance Verification of a Family
of Low-Lift Airfoils, EAWE, Paris, 2015. a
Chen, K. K. and Thyson, N. A.: Extension of Emmons' spot theory to flows on
blunt bodies, AIAA J., 9, 821–825, 1971. a
Davis, M., Reed, H., Youngren, H., Smith, B., and Bender, E.: Transition
Prediction Method Review Summary for the Rapid Assessment Tool for Transition
Prediction (RATTraP), US Air Force Research Lab. Technical Rep. VA-WP-TR-2005-3130, Wright–Patterson AFB, OH, 2005. a
Dhawan, S. and Narasimha, R.: Some properties of boundary layer flow during the transition from laminar to turbulent motion, J. Fluid Mech., 3, 418–436, 1958. a
Diakakis, K., Papadakis, G., and Voutsinas, S. G.: Assessment of transition
modeling for high Reynolds flows, Aerospace Sci. Tech., 85, 416–428, 2019. a
Dini, P., Selig, M. S., and Maughmer, M. D.: Simplified Linear Stability
Transition Prediction Method for Separated Boundary Layers, AIAA J., 30,
1953–1961, https://doi.org/10.2514/3.11165, 1992. a
Emmons, H.: The laminar-turbulent transition in a boundary layer – Part I, J. Aeronaut. Sci., 18, 490–498, 1951. a
Eppler, R.: Practical calculation of laminar and turbulent bled-off boundary
layers, Report number NASA-TM-75328, NASA Technical Memorandum, NASA,
Washington, D.C., 1978. a
FieldView: FieldView Reference Manual, Intelligent Light, Rutherford, NJ, 2017. a
Gleyzes, C., Cousteix, J., and Bonnet, J. L.: A Calculation Method of Leading Edge Separation Bubbles, in: Numerical and Physical Aspects of Aerodynamic Flows II, edited by: Cebeci, T., Springer, Berlin, Heidelberg, 1983. a
Hansen, M. O., Sørensen, N. N., and Michelsen, J.: Extraction of lift, drag and angle of attack from computed 3-D viscous flow around a rotating blade, in: 1997 European Wind Energy Conference, Irish Wind Energy
Association, Slane, 499–502, 1997. a
Herbert, T.: Parabolized stability equations, Annu. Rev. Fluid Mech., 29, 245–283, 1997. a
Hernandez, G. G. M., Sørensen, J. N., and Shen, W. Z.: Laminar-turbulent
transition on wind turbines, DTU Mechanical Engineering, Kgs. Lyngby, 2012. a
Johansen, J. and Sørensen, N. N.: Aerofoil characteristics from 3D CFD rotor computations, Wind Energy, 7, 283–294, https://doi.org/10.1002/we.127, 2004. a
Joseph, L. A., Borgoltz, A., and Devenport, W.: Infrared thermography for
detection of laminar–turbulent transition in low-speed wind tunnel testing,
Exp. Fluids, 57, 57–77, 2016. a
Krumbein, A.: Application of Transition Prediction, in: MEGADESIGN and MegaOpt –German Initiatives for Aerodynamic Simulation and Optimization in Aircraft Design, edited by: Kroll, N., Schwamborn, D., Becker, K., Rieger, H., and Thiele, F., Springer, Berlin, Heidelberg, 107–120, 2009. a
Kümmerer, H.: Numerische Untersuchungen zur Stabilität ebener laminarer Grenzschichtströmungen, PhD thesis, 1973. a
Langtry, R. B.: A correlation-based transition model using local variables for unstructured parallelized CFD codes, https://doi.org/10.18419/OPUS-1705, 2006. a
Larsen, T. and Hansen, A.: How 2 HAWC2, the user's manual, Denmark,
Risoe-R-1597, Forskningscenter, Risoe, 2007. a
Lobo, B., Boorsma, K., and Schaffarczyk, A.: Investigation into Boundary Layer Transition on the MEXICO Blade, J. Phys.: Conf. Ser., 1037, 052020, https://doi.org/10.1088/1742-6596/1037/5/052020, 2018. a
Mack, L. M.: Transition and Laminar Instability, No. NASA-CP-153203, NASA Jet
Propulsion Laboratory, California, 1977. a
Madsen, H. A.,Özçakmak,Ö. S., Bak, C., Troldborg, N.,
Sørensen, N. N., and Sørensen, J. N.: Transition characteristics measured on a 2 MW 80 m diameter wind turbine rotor in comparison with transition data from wind tunnel measurements, in: AIAA Scitech 2019 Forum,
January 2019 San Diego, California, https://doi.org/10.2514/6.2019-0801, 2019a. a, b
Madsen, M. H. A., Zahle, F., Sørensen, N. N., and Martins, J. R. R. A.: Multipoint high-fidelity CFD-based aerodynamic shape optimization of a 10 MW wind turbine, Wind Energ. Sci., 4, 163–192, https://doi.org/10.5194/wes-4-163-2019, 2019b. a
Mayle, R.: A theory for predicting the turbulent-spot production rate, in: ASME 1998 International Gas Turbine and Aeroengine Congress and Exhibition,
V001T01A071, American Society of Mechanical Engineers, New York, 1998. a
Menter, F.: Zonal two equation kw turbulence models for aerodynamic flows, in: 23rd fluid dynamics, plasmadynamics, and lasers conference, 6–9 July 1993, Orlando, FL, USA, p. 2906, 1993. a
Menter, F. R., Langtry, R. B., Likki, S., Suzen, Y., Huang, P., and Völker, S.: A correlation-based transition model using local variables – part II: model formulation, J. Turbomach., 128, 413–422, 2006. a
Michel, R.: Etude de la Transition sur les Profiles d'Aile; Etablissement
d'un Critére de Determination de Point de Transition et Calcul de la
Trainee de Profile Incompressible, ONERA Report 1/1578A, 1951. a
Michelsen, J. A.: Basis3D-a platform for development of multiblock PDE solvers, Tech. rep., Technical Report AFM 92-05, Technical University of Denmark, Denmark, 1992. a
Michelsen, J. A.: Block structured Multigrid solution of 2D and 3D elliptic
PDE's, Department of Fluid Mechanics, Technical University of Denmark, Denmark, 1994. a
Morkovin, M. V.: Critical evaluation of transition from laminar to turbulent
shear layers with emphasis on hypersonically traveling bodies, Tech. rep.,
Martin Marietta Corp Baltimore Md Research Inst. for Advanced Studies, Air Force Flight Dynamics Laboratory, Ohio, 1969. a
Morkovin, M. V.: Bypass Transition to Turbulence and Research desiderata, NASA, Lewis Research Center Transition in Turbines, 161–204, 1985. a
Özçakmak,Ö. S., Madsen, H. A., Sørensen, N., Sørensen, J. N., Fischer, A., and Bak, C.: Inflow Turbulence and Leading Edge Roughness
Effects on Laminar-Turbulent Transition on NACA 63-418 Airfoil, J. Phys.: Conf. Ser., 1037, 022005, https://doi.org/10.1088/1742-6596/1037/2/022005, 2018. a
Patankar, S. V.: Numerical heat transfer and fluid flow, Hemisphere Publ. Corp., New York, 1980. a
Patankar, S. V. and Spalding, D. B.: A calculation procedure for heat, mass and momentum transfer in three-dimensional parabolic flows, in: Numerical
Prediction of Flow, Heat Transfer, Turbulence and Combustion, Imprint, Pergamon, 54–73, 1983. a
Reichstein, T., Schaffarczyk, A. P., Dollinger, C., Balaresque, N., Schülein, E., Jauch, C., and Fischer, A.: Investigation of
Laminar–Turbulent Transition on a Rotating Wind-Turbine Blade of Multimegawatt Class with Thermography and Microphone Array, Energies, 12,
2102, https://doi.org/10.3390/en12112102, 2019. a
Reshotko, E.: Stability theory as a guide to the evaluation of transition
data., AIAA J., 7, 1086–1091, https://doi.org/10.2514/3.5279, 1969. a
Reza, T. Z. and Amir, K.: Prediction of boundary layer transition based on
modeling of laminar fluctuations using RANS approach, Chin. J. Aeronaut., 22, 113–120, 2009. a
Rhie, C. and Chow, W.: A numerical study of the turbulent flow past an isolated airfoil with trailing edge separation, in: 3rd Joint Thermophysics, a
Schaffarczyk, A. P., Schwab, D., and Breuer, M.: Experimental Detection of
Laminar-Turbulent Transition on a Rotating Wind Turbine Blade in the Free
Atmosphere, Wind Energy, 20, 211–220, https://doi.org/10.1002/we.2001, 2017. a
Schaffarczyk, A. P., Boisard, R., Boorsma, K., Dose, B., Lienard, C., Lutz, T., Madsen, H. Å., Rahimi, H., Reichstein, T., Schepers, G., Sørensen, N., Stoevesandt, B., and Weihing, P.: Comparison of 3D transitional CFD
simulations for rotating wind turbine wings with measurements, J. Phys.: Conf. Ser., 1037, 022012, https://doi.org/10.1088/1742-6596/1037/2/022012, 2018. a
Schepers, J. and Snel, H.: Model experiments in controlled conditions, ECN
Report ECN-E-07-042, ECN, the Netherlands, 2007. a
Schwab, D., Ingwersen, S., Schaffarczyk, A. P., and Breuer, M.: Aerodynamic
Boundary Layer Investigation on a Wind Turbine Blade under Real Conditions,
in: Wind Energy – Impact of Turbulence, edited by: Hölling, M., Peinke,
J., and Ivanell, S., Springer, Berlin, Heidelberg, 203–208, 2014. a
Smith, A. and Gamberoni, N.: Transition, pressure gradient, and stability
theory, Report no. es. 26388, Douglas Aircraft Co, Inc., El Segundo, CA, 1956. a
Sørensen, N. N.: General Purpose Flow Solver Applied to Flow Over Hills,
PhD thesis, Risø National Laboratory, Risø, 1995. a
Sørensen, N. N.: HypGrid2D. A 2-d mesh generator, Tech. rep., Risø National Laboratory, Risø, 1998. a
Sørensen, N. N.: CFD modelling of laminar-turbulent transition for airfoils and rotors using the γ-model, Wind Energy, 12, 715–733,
https://doi.org/10.1002/we.325, 2009. a, b
Sørensen, N. N., Bechmann, A., and Zahle, F.: 3D CFD computations of
transitional flows using DES and a correlation based transition model, Wind
Energy, 14, 77–90, 2011. a
Sørensen, N. N., Zahle, F., and Michelsen, J. A.: Prediction of airfoil performance at high Reynolds numbers EFMC, Sound/Visual production (digital), Kgs. Lyngby, Denmark, 2014. a
Stock, H. and Degenhart, E.: A simplified e exp n method for transition
prediction in two-dimensional, incompressible boundary layers, Z. Flugwiss. Weltraumforsch., 13, 16–30, 1989. a
Stock, H. W. and Haase, W.: Feasibility Study of e Transition Prediction in
Navier–Stokes Methods for Airfoils, AIAA J., 37, 1187–1196, 1999. a
Suder, K. L., Obrien, J. E., and Reshotko, E.: Experimental study of bypass
transition in a boundary layer, MsT, NASA Lewis Research Center, Case Western Reserve Univ., Cleveland, Ohio, p. 20, 1988. a
Suzen, Y. and Huang, P.: Modeling of flow transition using an intermittency
transport equation, J. Fluids Eng., 122, 273–284, 2000. a
Van Ingen, J. L.: A Suggested Semi-Empirical Method for The Calculation of the Boundary Layer Transition Region, Tech. Rep. No. V.T.H.-74, Delft University of Technology, Delft, 1956. a
Von Kármán, T.: Uber laminare und turbulente Reibung, Z. Angew. Math.
Mech., 1, 233–252, 1921. a
Walters, D. K. and Leylek, J. H.: A new model for boundary layer transition
using a single-point RANS approach, J. Turbomach., 126, 193–202, 2004. a
Wazzan, A., Okamura, T., and Smith, A.: Spatial and temporal stability charts
for the Falkner–Skan boundary-layer profiles, Tech. rep., McDonnell Douglas
Astronautics Co-Hb, Huntington Beach, CA, 1968. a
Welch, P.: The use of fast Fourier transform for the estimation of power
spectra: a method based on time averaging over short, modified periodograms,
IEEE T. Audio Electroacoust., 15, 70–73, 1967. a
Yilmaz, Ö. C., Pires, O., Munduate, X., Sørensen, N. N., Reichstein, T., Schaffarczyk, P., Diakakis, K., Papadakis, G., Daniele, E., Schwarz, M., Lutz, T., and Prieto, R.: Summary of the blind test campaign to predict the high Reynolds number performance of DU00-W-210 airfoil, in: 35th Wind Energy Symposium, 9–13 January 2017, Grapevine, Texas, p. 0915, 2017. a
Short summary
Accurate prediction of the laminar-turbulent transition process is critical for design and prediction tools to be used in the industrial design process, particularly for the high Reynolds numbers experienced by modern wind turbines. Laminar-turbulent transition behavior of a wind turbine blade section is investigated in this study by means of field experiments and 3-D computational fluid dynamics (CFD) rotor simulations.
Accurate prediction of the laminar-turbulent transition process is critical for design and...
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