高速列车表面气动噪声源的频谱分析

When running speed of a high speed train is over 300km/h, the aerodynamic noise induced by the train will be larger than the acoustic sound induced between wheel and track or induced by electromagnetism devices. Dipole sound source distributing on the surface of train may be the most main aero acoustic source. Therefore, researchers pay much attention to invastigation of the distribution state and acoustic intensity on the surface of train. Large eddy simulation method is used to solve the fluid field equations around a high-speed train. From the solutions of these equations, aerodynamic pressure pulsation distributed on the train surface is obtained. Consequently, the pressure pulsation definition in time domain is converted to sound intensity definition in frequency domain by Fourier transform. After that, the characteristic of frequency spectrum of dipole source intensity at any point can be obtained. Calculation results show that the maximum value of dipole sound intensity appears the frequency lower 1000Hz, large sound intensity appears at the position of separate eddy and the maximum sound intensity appears at position of the first bogie.