Aerodynamic Noise Numerical Simulation And Design Studies Of Wind Turbine Airfoil

With the rapid development of the wind turbine, aerodynamic noise problem has become one of the major constraints, and therefore the study of wind turbine noise is an important issue in the development process of wind turbine. In this article, wind turbine airfoil S809 is selected as a model and the semi-empirical algorithm and a combined method of computational fluid dynamics and computational aeroacoustics are used, respectively, to predict airfoil noise with foci of the generation and propagation characteristics of trailing edge noise.An airfoil with variable trailing edge will produce changes of aerodynamic performance, while it has an impact on the aerodynamic noise flowing through the airfoil. To evaluate the aerodynamic performance and the aerodynamic noise level of the airfoil edge deflection, the airfoil self-noise model is studied and the NASA self-noise model based on extensive experiments is applied for the airfoil aerodynamic noise prediction. In order to get better aerodynamic performance and low aerodynamic noise level corresponding to the angle of attack, selecting the airfoil S809 as model, taking life-to-drag ratio and noise level as optimization objectives, an optimization method is set up to design the point and angle of the airfoil trailing edge deflection. The design results are then applied to the NREL 10m-diameter blade, validating the optimization.In terms of numerical simulation of aerodynamic noise, a method base on LES/FW-H combination is used for the unsteady numerical simulation of NACA0018 and S809 airfoil flow fields and sound fields, followed by detailed analysis of the trailing edge acoustic characteristics. On this basis, the aerodynamic noise characteristics of S809 with blunt trailing edge was designed and analyzed. The numerical result shows the effect of the blunt trailing edge of the aerodynamic noise.