Wind turbine noise mechanisms and some concepts for its control

Abstract

The aerodynamic noise production mechanisms of modern horizontal axis wind turbines are reviewed. An engineering analysis of the time and frequency scales from three noise sources, leading edge turbulence interaction noise, trailing edge noise and blade-tower interaction noise is presented. The analysis shows that noise sources are present from low-frequencies (1-4 Hz) to over 500 Hz for a representative wind turbine. The results of the analysis are used to explain amplitude modulation observed during noise measurements at a European wind farm. The paper concludes with a description of conceptual ideas for the control of wind turbine noise.