풍력터빈의 후류 우회를 위한 요각도 분석

Abstract

The wake deficit from wind turbines is a major factor in reducing the performance of wind farms. Numerous studies have been performed on yaw angle control for the wind turbine rotor to mitigate the wake effect. It is necessary to establish a physical understanding of wake deflection and deformation at various yaw angles. In the present study, the turbine wake development at various yaw angles(-30° ~ 30°) and inflow wind speeds(7 ~ 9m/s) were analyzed via Large-Eddy Simulation coupled with Actuator Disk Model. Simulations were performed under uniform inflow conditions with the NREL 5MW wind turbine model placed at the center. The center, width, and shape of wake deficit profiles were calculated based on the velocity field and the vorticity of the wake. It shows that as the wake center deflection did not increase linearly with the yaw angle, and the slope of the wake deflection varied from the starting point to the end. In addition, the asymmetry of the wake distributions was analyzed based on the vorticity field which evolved into a kidney-shaped wake profile. Lastly, it was found that the wake deficit distribution held a self-similarity profile for the given range of uniform inflows.