高速列车头型近场与远场噪声预测

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

摘要:

建立了某头型的1∶8缩比三车编组气动噪声仿真模型，采用大涡模拟获得车身湍流脉动压力，基于FWH方程和声扰动方程分别获得远场噪声和近场噪声，从而建立一整套头型气动噪声预测方法.远场测点总声压级的仿真结果与风洞试验结果相差小于2.0 dB(A)，频谱变化趋势相同，量级相差较小，表明基于FWH方程得到远场噪声的可行性.基于声扰动方程能够获得头型关键部位的总声压级，通过对比量级发现，转向架部位总声压级量级远大于其他部位，这与传声器阵列识别结果相吻合，从而验证了声扰动方程获得近场噪声结果.对比头型各部位湍流脉动总压力级和总声压级发现，转向架和排障器量级大于车窗、鼻锥和车体；与湍流脉动总压力级相比，总声压级分布更为均匀，量级更小.

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.