Wake characteristics of wind turbine in anisotropic terrain based on field experiment combined with LES

Abstract

Due to the complexity of the terrain-wake coupling effect, accurate evaluation of wake characteristics is critical for power production and the safety of complex terrain wind farms. This study delves into the wake characteristics (wake velocity field, wake deficit, and wake expansion) in different terrain conditions combined LiDAR-based field experiment with large eddy simulation (LES). LES was conducted to investigate the influence of pressure gradient and turbulence intensity on the wake development and decouple the terrain effect on the turbine wake. Several commonly used models for wake centerline and wake expansion are evaluated by the field measured data. Theoretical analysis for the results of multi-methodology indicates that the unfavorable pressure gradient has a great influence on the wake structure and wake velocity deficit in leeward slope cases. In addition to the impact of atmospheric coherent turbulence, the terrain inducement effect makes the wake meandering characteristics more remarkable. Turbulent kinetic energy analysis reveals that stronger turbulence intensity in the upper wake layer exacerbates the vertical asymmetry of wake velocity. This study provides better guidance for control strategies and power enhancement of wind turbines in complex terrain.