Sound Source Analysis of Blade Aerodynamic Noise of Megawatt Wind Turbine Based on Vortex Sound Theory

Abstract

Based on the analysis method of vortex sound theory, the mechanism of turbine blade aerodynamic noise generation is studied. In this paper, modeling and grid division of wind turbine blades and flow field areas are first carried out, and the directivity of wind turbine aerodynamic noise is analyzed by CFD (computational fluid dynamics) numerical simulation calculation. Through test verification, it is concluded that wind turbine aerodynamic noise is a dipole characteristic, and the accuracy of numerical simulation is verified. Then, the distribution of flow field and sound field calculated by numerical simulation are analyzed and compared, and the main causes of wind turbine blade aerodynamic noise are studied. The results show that the aerodynamic noise sources of wind turbine blades are mainly distributed in 65%~95% span of the blade spanwise direction. At the same time, the sound source of wind turbine blade aerodynamic noise is mainly caused by vortex movement caused by fluid movement, and the distribution law of vortex movement in the range of 65%~95% of blade span is very consistent with the distribution law of blade aerodynamic noise.