明线上与隧道内高速列车流场结构及气动噪声源

基于成熟的明线上高速列车气动噪声计算模型和可压缩大涡模型,考虑声学无反射边界条件,利用计算流体力学软件Fluent建立无限长隧道内高速列车气动噪声计算模型,对比分析高速列车在明线上与隧道内运行时的流场组织结构和气动噪声源。结果表明:高速列车在明线上与隧道内运行时具有类似的流场结构和气动噪声源分布规律,但隧道内的流场结构尺度与强度、气动噪声源强度均比明线上大;车速为350 km·h-1时,隧道内头车排障器尖点扰动区的速度幅值约为明线上的1.2倍,列车尾流区长度约为明线上的1.7倍,整车、1位转向架、头车流线型车底及中间车上部的等效声源声功率分别约为明线上的3.2倍、1.6倍、2.7倍和4.2倍;隧道内活塞效应并不是在全频率范围增加等效声源声功率,而是在包含峰值频率较狭窄的频率范围显著地增加等效声源声功率。

Flow Field Structure and Aerodynamic Noise Source of High-Speed Train on Open Track and in Tunnel

Based on the mature aerodynamic noise calculation model of high-speed train on open track and the compressible large eddy model,considering the acoustic non-reflection boundary condition,the computational fluid dynamics software FLUENT is used to establish the aerodynamic noise calculation model of high-speed train in infinite length tunnel.The flow field structure and aerodynamic noise source of high-speed train running on the open track and in the tunnel are compared and analyzed.Results show that the flow field structure and aerodynamic noise source distribution of high-speed train running on the open track and in the tunnel are similar,but the scale and intensity of the flow field structure and the intensity of aerodynamic noise source in the tunnel are larger than those on the open track.When the train speed is 350 km·h-1,the velocity amplitude of the disturbance zone around the cowcatcher of the head car in the tunnel is about 1.2 times of that on the open track.The length of the train wake zone in the tunnel is about 1.7 times of that on the open track.The equivalent sound power of the whole vehicle,the first bogie,the streamlined bottom of the head car and the upper part of the middle car in the tunnel is 3.2,1.6,2.7 and 4.2 times of that on the open track,respectively.The piston effect in the tunnel does not increase the equivalent sound power in the full frequency range,but significantly increases the equivalent sound power in the narrow frequency range with peak frequency.