Study Of The Influence Of The Doppler Effect To High-Speed Train Acoustic Field Reconstruction

Recent years, our high speed train and high speed railway have a rapid development, and in the top position of the world. However, the problem of noise pollution caused by high speed railway is getting more and more attention. With the acceleration of the operating speed of the train, the noise pollution to the environment along have more serious impact. In order to provide reference of reducing the vibration and noise from the high speed train, several research institutes conducted researches about noise source identification and acoustic field reconstruction. However, the relative movement of high-speed train’s noise source and fixed acoustic test array led to the Doppler effect of the acoustic signal generated, than, the acoustic field data distortion. This article, for the very first time, proposed the Doppler effect correction technology of high-speed train acoustic field reconstruction, through the adjusted Doppler acoustic field and original acoustic field comparative analysis, to get the conclusion on the influence of the Doppler effect to high-speed train acoustic field reconstruction.This paper, starting from the basic theory of high-speed train traditional acoustic field reconstruction, analyzed the configuration of high-speed train noise source and the principle of acoustic field reconstruction based on WSM (Wave Superposition Method). It concluded the equivalent acoustic field reconstruction method of high speed train, and after that, it analyzed the Doppler-effect of acoustic signal, and get the Doppler time correction and Doppler frequency domain correction analysis. Finally, it planted the DCM (Doppler correction methods) in the acoustic field reconstruction algorithm based on WSM. Through calculating the results of the acoustic field with DCM and no DCM, it concluded that the influence of the Doppler-effect to high-speed train acoustic field reconstruction. The main content of this paper is as follows:The first part of this essay is the theoretical analysis of the high-speed train acoustic field reconstruction and programming with MATLAB language, including high-speed train complex noise source configuration analysis, and the application of WSM in the acoustic field reconstruction, and the Doppler correction theory, etc. We use MATLAB software programming, based on WSM programming and Doppler correction algorithm embedded programming respectively.Second, we established the confirmatory test, including fixed double sound source acoustic field reconstruction test outdoor and moving sound source acoustic field reconstruction test. We verify the validity of the acoustic field reconstruction method based on WSM and the effectiveness of Doppler correction in the acoustic field calibration. The experimental results show that’s very good.Finally, we tested the acoustic field of the high-speed train on the actual railway. During the test, we have tested the Multi-speed of two different high-speed train. We analyze the results of acoustic field reconstruction of different train under different speed and conducted the Doppler correction. Finally, by comparing the results to analyze the influence of the Doppler Effect to high-speed train acoustic field reconstruction, we concluded that the closer distance to the train surface, the larger effect of the Doppler Effect we get, also has certain influence to the far field. This effect will increase with the increasing of the train’s running speed in the far field.