Prediction of Near Field and Far Field Noise for High-speed Train Head Shape

Abstract:

Establishing aerodynamic noise prediction method for high-speed train head helps to quickly obtain the aerodynamic noise characteristics produced by the interaction between the head and airflow. For this purpose, the aerodynamic noise simulation model of 1∶8 contraction ratio of three connected vehicle was established. The large eddy simulation was used to obtain the body turbulent fluctuation pressure. Based on the FW-H equation and the acoustic perturbation equation, far-field noise and near-field noise were respectively obtained. Then a set of prediction methods for aerodynamic noise were established. The difference between the simulation results of the total sound pressure level in the far field measuring point and the wind tunnel test was less than 2.0 dB(A). Their spectrum change trends were the same, and the magnitudes were relatively small, indicating the feasibility of obtaining far-field noise based on the FW-H equation. Based on the acoustic perturbation equation, the total sound pressure level of the key parts of the head region could be obtained. Comparison of the magnitudes showed that the total sound pressure level of the bogie was far greater than that of other parts. And this was consistent with the microphone array recognition results. So the near-field noise result obtained from the acoustic perturbation equation was verified. By comparing the turbulent pulsation total pressure level and the total sound pressure level in the different parts of the head type, it was found that the level of the bogie and the obstacle protector were greater than that of the window, nose cones and body. Compared with the total pressure level of turbulent pulsation, the total sound pressure level distribution was of a better uniform and the magnitude was smaller.