Experimental investigation to clarify the wake structure of a floating wind turbine

(Periodic fluctuation of wakes caused by pitch motion)

Abstract

The wakes of a wind turbine with a fixed foundation are mostly understood. However, the wakes of a floating offshore wind turbine become complex due to the motion of the floating foundation, so further knowledge is needed. In this study, a device simulating a floating wind turbine was developed, and the wakes of the model wind turbine were measured when the Strouhal number (St) was 0.08, and the amplitude of the pitch oscillation was 5 degrees. By applying the phase-averaging method to the wake measurement data, the behavior of the wake during pitch motion was clearly expressed. It was found that the distribution of wakes shifted vertically with time and returned to the original distribution over one cycle.