高速列车通过隧道-桥梁-隧道时车体的气动效应

以我国高速铁路沿线上某座隧道-桥梁-隧道基础设施为工程背景,基于计算流体力学和多孔介质理论建立了列车-隧道-桥梁-风屏障-空气三维CFD数值仿真模型,研究了列车运行于隧-桥-隧全过程的气动荷载变化特性.针对横风环境中列车运行于桥隧相连段的过程,从流场角度进一步揭示了风屏障的存在与否对气动荷载突变效应的影响.结果表明:1)无风屏障条件下,各节车厢在"由桥至隧"过程的气动荷载波动幅度是"由隧至桥"过程中相应值的1.03～1.89倍,而风屏障的存在将使两过程中气动荷载波动幅度基本相等;2)列车气动横向力的变化对风屏障的影响最为敏感,而气动升力和俯仰力矩的敏感性相对较弱.

Aerodynamic Effects of High-speed Trains when Passing through Tunnel-Bridge-Tunnel

A tunnel-bridge-tunnel (TBT) infrastructure along the high-speed railway in China is taken as the engineering background, based on the theory of CFD and porous media, a 3D CFD numerical simulation model of train-tunnel-bridge-wind barrier-air is established. The aerodynamic load variation characteristic of the train when running on the TBT is studied. Aiming at the process of train running on the bridge-tunnel connection section (BTCS) under crosswind environment, the influence of the existence of wind barrier on the transient change effect of the aerodynamic load is further revealed from the view of the flow field. The results show that: 1) Under the condition without wind barrier, the fluctuation amplitudes of aerodynamic loads of each carriage in the process of ''from bridge to tunnel'' are 1.03~1.89 times of the corresponding values in the process of ''from tunnel to bridge'', and the existence of wind barrier makes the fluctuation amplitudes of aerodynamic loads in the two processes basically equal. 2) The change of train aerodynamic side force is most sensitive to the influence of the wind barrier, while the sensitivity of aerodynamic lift force and pitching moment is relatively weak.