Exploring the impact of wind veer on the aerodynamic performance and wake evolution of a wind turbine

As wind turbine dimensions continue to expand, the influence of wind veer has become progressively more notable, necessitating in-depth assessment. Based on the IEA 15 MW wind turbine scaled model, large eddy simulations are performed in this study to explore wind turbine aerodynamics under varied veering wind conditions. Considering the effects of yaw angle and rotor rotation direction, the mechanisms through which wind veer affects the turbine aerodynamic loads, power output, and wake evolution are systematically analyzed. The findings reveal that wind veer modifies the spatial distribution of average blade aerodynamic loads, and primarily acts on the 1P and 2P frequency components in the fluctuating loads, with the variation law closely tied to rotor rotation direction. The output power decreases with increasing wind veering degree: the maximum power loss reaches 5% under non-yawed conditions and exceeds 10% under yawed conditions. On the other hand, the wind veer accelerates the recovery of wake velocity deficit, with a significant anisotropic feature in the wake evolution: wind veer enhances lateral wake expansion while weakening vertical expansion, resulting in a clockwise-inclined elliptical wake cross-section. Furthermore, the wind veer causes the counter-rotating vortex pair (CVP) in yawed wakes to tilt asymmetrically, reconfiguring the vortex structures and leading to severe wake distortion or even splitting.