高速列车隧道进口波基本特性数值研究

Numerical research on basic characteristics of tunnel entry waves induced by a high-speed train running into the tunnel

采用有限体积方法和任意滑移界面动网格技术的CFD方法,对CRH380A高速列车和我国隧道条件下进口波基本特性进行了数值模拟研究。采用PISO算法和SSTk-ω高雷诺数湍流模型求解高速列车通过隧道引起的三维可压缩非定常的空气湍流流动。为避免数值计算产生不合理的物理现象,应用了光滑启动技术。通过与日本有关试验数据和数值模拟结果的对比研究,验证了本文数值方法的正确性。在此基础上,以CRH380A高速列车为例,分析了高速列车引起近场和远场的压力波动特性及其与进口波的区别,得出了进口波具有朝向列车前进方向的指向性,归纳出其幅值与列车速度的三次方成正比的关系。频谱分析表明隧道进口波的主频小于7Hz,频谱幅值和声压级离隧道端口越远则越小,高速列车头尾部流线型较好时进口波对外部环境的影响较小。

Though tunnel entry waves belong to the category of infrasound and are usually weaker than micro-pressure waves,they could cause a new environmental problem with further speed up of future high-speed trains.In the present study,numerical investigation of the tunnel entry waves induced by a high-speed train CRH380A running into a typical China tunnel is per-formed using a CFD code STAR-CD and adopting arbitrary sliding interface（ASI）method,which is based on the finite volume method（FVM）.To solve the governing equations of three dimen-sional,compressible and unsteady turbulent air flow around the high-speed train,the PISO algo-rism and Shear-Stress Transport （SST）k-ω turbulence model are used.The high-speed train is allowed to accelerate gradually from stationary to a constant speed in order to avoid unphysical pressure fluctuation in air flow during numerical iteration.The validity of the present numerical method is carried out through a preliminary study on a revolutionary ellipsoid train model,of which the experimental and numerical results are accessible from literatures of Japan scholars. Thereafter,taking high-speed train CRH380A as an example,based on analysis of variation per-formance of a moving quasi-steady pressure field,i.e.passing-train pressure field,the basic characteristics of tunnel entry waves are revealed.It is also showed that the tunnel entry wave has directivity towards the forward direction of the train.Study on the train speed dependency shows that the magnitude of entry waves is proximately proportional to the cube of the train speed,implying that the higher the train speed,the more noticeable the tunnel entry waves and its influence.Furthermore,the spectral analysis shows that the main frequency of tunnel entry waves is less than 7 Hz,and the magnitude and SPL of it are decrease along its propagation.＆nbsp;However,the influence of tunnel entry waves induced by CRH380A on surroundings is rather weak because of its slender nose and tail shape.