真空管道高速列车气动噪声源特性分析

Simulation of Noise Source for High Speed Train in Evacuated Tube

为研究真空管道中高速列车的气动噪声源特性，建立低压环境下真空管道高速列车空气动力学计算的流体模型、数学模型和数值模型，以及高速列车偶极子噪声源和四极子噪声源的计算模型，研究管道压力、列车速度和阻塞比对真空管道高速列车偶极子噪声源和四极子噪声源的影响。计算结果表明，在低压（10^3～10^4Pa）环境下，真空管道中的空气流动可以采用连续介质模型描述。高速列车偶极子噪声源和四极子噪声源均与车速的对数成线性关系，当车速为600km／h时，四极子噪声源较小，偶极子噪声源占据主导地位，随着列车速度的提高，四极子噪声源变得明显，并占据主导地位。降低管道压力和阻塞比可以有效减小高速列车气动噪声源的强度。

The dynamic situation, involving a high speed train traveling in the evacuated tube, was modeled, approximated, and simulated to analyze the aerodynamic noise sources. The influence of the physical conditions, such as the pressure in the tube, speed, and blockage ratio, on the dipole and quadrupole models of the noise sources was simulated. The simulated results show that in the low pressure range （ 10^3 - 10^4 Pa）, the continuum model works pretty well in describing the air flow. The dipole and quadrupole noise sources depend linearly on the logarithm of the train speed. When it comes to the noise intensity at a speed of 600 km/h, the dipole noise source significantly outweighs the quadrupole noise source. As the speed increases, the quadrupole noise source plays an increasingly important role and finally prevails over the dipole noise source. The noise intensity can be considerably reduced by lowering both the pressure and the blockage ratio.