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Effects of tip speed ratio on wind turbine wake meandering

Published online by Cambridge University Press:  25 June 2025

Yan Wang Open the ORCID record for Yan Wang [Opens in a new window] ,
Guihua Zhao ,
Guoliang Liu ,
Yongze Zhou ,
Mingwei Ge Open the ORCID record for Mingwei Ge [Opens in a new window] ,
Zhen Ouyang ,
Zijing Ding Open the ORCID record for Zijing Ding [Opens in a new window]  and
Ruifeng Hu Open the ORCID record for Ruifeng Hu [Opens in a new window]
Yan Wang
Affiliation:
School of Energy and Power Engineering, Lanzhou University of Technology, Lanzhou 730050, PR China
Guihua Zhao
Affiliation:
School of Energy and Power Engineering, Lanzhou University of Technology, Lanzhou 730050, PR China
Guoliang Liu
Affiliation:
School of Energy and Power Engineering, Lanzhou University of Technology, Lanzhou 730050, PR China
Yongze Zhou
Affiliation:
Center for Particle-Laden Turbulence, Key Laboratory of Mechanics on Disaster and Environment in Western China, Ministry of Education and College of Civil Engineering and Mechanics, Lanzhou University, Lanzhou 730000, PR China
Mingwei Ge
Affiliation:
State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing 102206, PR China
Zhen Ouyang
Affiliation:
School of Energy Science and Engineering, Harbin Institute of Technology, Harbin 150001, PR China
Zijing Ding
Affiliation:
School of Energy Science and Engineering, Harbin Institute of Technology, Harbin 150001, PR China
Ruifeng Hu*
Affiliation:
Center for Particle-Laden Turbulence, Key Laboratory of Mechanics on Disaster and Environment in Western China, Ministry of Education and College of Civil Engineering and Mechanics, Lanzhou University, Lanzhou 730000, PR China
*
Corresponding author: Ruifeng Hu, hurf@lzu.edu.cn
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Abstract

This study utilises large-eddy simulation with the actuator line model to examine the effects of the tip speed ratio (TSR) on the wake-meandering characteristics of a wind turbine in uniform and turbulent inflows. It is shown that as the TSR grows, the onset position of the wake meandering moves closer to the rotor, and the magnitude of wake oscillation is stronger. This aligns with previous work showing that a higher TSR can accelerate the instability and breakdown of tip vortices. Without a nacelle, the Strouhal number of the wake meandering is found to be independent of the TSR under both the uniform and turbulent inflows. However, with a relatively large nacelle, the Strouhal number first increases and then decreases with TSR. Therefore, the current discovery elucidates the crucial role of the nacelle and clarifies the origin of the TSR dependence of the Strouhal number in wake meandering. In addition, the characteristic frequency of the wake meandering under the turbulent inflow is much smaller than that under the uniform inflow, because of the significant influence of the freestream turbulence. Furthermore, the proper orthogonal decomposition (POD) and spectral POD (SPOD) methods are employed to study the spatiotemporal characteristics of the meandering wake and its TSR dependence. It is found that the tip and root vortices are the prominent wake structures under the uniform inflow, whereas more complex multiscale structures from the interaction between the freestream turbulence and tip/root vortices exist under the turbulent inflow. Moreover, an amplitude modulation phenomenon of the POD time coefficients at the optimal TSR is observed in the uniform inflow case. Finally, a reduced-order model is constructed for predicting the wake dynamics by combining the SPOD and the ‘sparse identification of nonlinear dynamics’ algorithm with high accuracy and interpretability.

JFM classification

Wakes/Jets: Wakes Turbulent Flows: Turbulence simulation Nonlinear Dynamical Systems: Low-dimensional models

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JFM Papers
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Journal of Fluid Mechanics , Volume 1014 , 10 July 2025 , A3
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© The Author(s), 2025. Published by Cambridge University Press

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