Determination of significant sources generating low-frequency noise in horizontal axis wind turbines

Several studies show that the Low-Frequency Noise (LFN) of wind turbines could have harmful effects on human health even when it is infrasound. In traditional classifications, the LFN of upwind turbines is referred only to steady thickness and steady loading sources, and the effect of vortices is considered negligible. In this study, the LFN of a horizontal axis wind turbine is simulated in wind speeds of 5-25 m/s by using a hybrid approach. The results show that vortices being far from blades have a significant effect on the LFN. It is also observed that the position received maximum LFN is far from the point introduced by the IEC 61400-11 standard for measuring the noise of horizontal axis wind turbines.