Noise Control Prediction Of High-Speed Railway Sound Barrier And Preliminary Study On External Vehicle Noise Doppler Effect

For the noise control effects prediction analysis of350km/h speed level high-speed railway sound barrier, based on boundary element method, the noise control effects prediction analysis model of high-speed railway sound barrier is established. The source identification results collected by wheel arrays system are used as the model’s input, containing sound source distribution, sound power level and spectrum characteristics. In this model, multiple reflection between car body and sound barrier and sound absorption material on sound barrier surface are taken into consideration. The noise control effect of sound barrier is estimated by acoustic response of standard points, distribution of acoustic field, and insertion loss of sound barrier using numerical method. The main research work in the present thesis involves:1) With the noise control effects prediction analysis model of high-speed railway sound barrier, the effect of the sound barrier height on insert loss is compared, on this basis, multiple reflections between car body and sound barrier and sound absorption material on sound barrier surface are considered.2) A comparative analysis of different head forms sound barrier is first considered. Then, the contrastive analysis is made with different head forms sound barrier and vertical sound barrier under consideration of multiple reflections between car body and sound barrier or sound absorption material on sound barrier surface as well as both are considered simultaneously.3) Based on the detailed analysis of frequency shift and acoustic pressure amplitude changing of Doppler effects, both are introduced into the study of high-speed railway outer noise. It mainly includes Doppler shift and acoustic pressure amplitude changing of typical evaluation points,the effect of relative position between sound source and receiver point on received frequency and acoustic pressure amplitude under typical frequency of high-speed railway outer noise main spectrum range,and the preliminary study on Doppler effect of a single continuous spectrum source.