Application of a LES technique to characterize the wake deflection of a wind turbine in yaw

TLDR

When a wind turbine operates in yaw, the wake deflects and its intensity and power output decrease slightly, affecting downstream turbines and increasing turbulence, which can reduce overall farm power and increase fatigue loads. The study aims to characterize wake deflection across yaw angles and thrust coefficients to enable active yaw control that steers wakes away from downstream turbines, improving farm performance. A large‑eddy simulation model with realistic wind boundary conditions was used to simulate turbine wakes, and the results were compared with particle image velocimetry experiments and simple analytical correlations. © 2009 John Wiley & Sons, Ltd.

Abstract

Abstract When a wind turbine works in yaw, the wake intensity and the power production of the turbine become slightly smaller and a deflection of the wake is induced. Therefore, a good understanding of this effect would allow an active control of the yaw angle of upstream turbines to steer the wake away from downstream machines, reducing its effect on them. In wind farms where interaction between turbines is significant, it is of interest to maximize the power output from the wind farm as a whole and to reduce fatigue loads on downstream turbines due to the increase of turbulence intensity in wakes. A large eddy simulation model with particular wind boundary conditions has been used recently to simulate and characterize the turbulence generated by the presence of a wind turbine and its evolution downstream the machine. The simplified turbine is placed within an environment in which relevant flow properties like wind speed profile, turbulence intensity and the anisotropy of turbulence are found to be similar to the ones of the neutral atmosphere. In this work, the model is used to characterize the wake deflection for a range of yaw angles and thrust coefficients of the turbine. The results are compared with experimental data obtained by other authors with a particle image velocimetry technique from wind tunnel experiments. Also, a comparison with simple analytical correlations is carried out. Copyright © 2009 John Wiley & Sons, Ltd.