高速列车转向架区域裙板对流场与气动噪声的影响

Effect of Bogie Fairing on Flow and Aerodynamic Noise Behaviour Around Bogie of High-Speed Train

运用声学比拟理论,采用1∶10简化模型对高速列车转向架部位气动噪声进行数值计算,并分析裙板对转向架部位流动与气动噪声性能的影响.基于延迟分离涡模型数值求解Navier-Stokes方程获得近场流场,运用考虑对流效应的Ffowcs Williams-Hawkings方程的声预测程序进行远场声辐射计算.结果表明,由于转向架舱在车体侧墙与底部形成表面不连续结构,流体通过转向架部位时产生了不同尺度和方向的复杂涡结构,上游几何体周围产生的涡向下游传播并与下游几何体相互作用,从而在转向架后端形成高湍流度尾流区.转向架区域外侧安装裙板后,流体与转向架舱的相互作用被削弱.靠近转向架并与车体侧墙平行的可穿透积分面的噪声预测结果显示,裙板可以在较宽频段内有效降低转向架部位的气动噪声.

The influence of a bogie fairing on the aerodynamic and aeroacoustic behaviour of flow past a simplified high-speed train bogie located in a bogie cavity at a scale of 1.＂ 10 was studied using a two-stage hybrid method comprising computational fluid dynamics and acoustic analogy. The near-field unsteady flow was obtained by solving the Navier-Stokes equations numerically with the delayed detached-eddy model and the results are used to calculate the far-field noise through a noise prediction code based on the convective Ffowcs Williams-Hawkings method. It is found that due to the surface shape discontinuity in the bogie cavity along the carbody side and bottom walls, a highly turbulent flow is generated within the bogie cavity. The vortices formed behind the upstream geometries are convected downstream and impinge on the downstream bodies, generating a highly turbulent wake behind the bogie. When the fairing is mounted around the bogie cavity, the interaction between the flow and the bogie cavity is reduced. The results show that the bogie fairing is effective in reducing the noise generated in most of the frequency range for the current model case based on predictions of the noise radiated to the trackside using a permeable data surface close to the bogie and parallel to the carbody side wall.