横风下高速列车在隧道洞口交会非定常气动效应

Unsteady aerodynamic effects of high-speed trains intersection at tunnel entrance under crosswind

针对横风下高速列车在洞口交会时的非定常气动问题,考虑流场的三维、可压缩、湍流特性,建立隧道-列车三维空气动力学模型,利用滑移网格技术模拟列车交会过程,采用SSTκ-ω湍流模型对列车交会全过程进行求解,研究横风对隧道内瞬变压力、列车风及流场分布特性的影响规律.研究结果表明:横风下列车交会时,洞口处气动压力系数变化幅值显著增大,交会完成时,列车之间压力系数峰-峰值较无横风情形增大30.6%;列车交会开始和完成时气动压力均发生突变,隧道中部附近气动压力峰值最大;横风下列车交会气动压力大小与空间位置有关,交会时列车间气动压力变化幅值分别是列车迎、背风侧压力变化幅值的2.2和1.5倍;横风对洞口附近列车风影响显著,横风时迎风侧列车风峰值最大,无横风时背风侧列车风峰值最大,且前者是后者的2.04倍;隧道内气动效应受横风影响范围有限,当横风为30 m/s、车速为350 km/h时,隧道内气动效应受影响范围为120 m;横风下交会开始与完成时,流场分布急剧变化,导致气动压力与列车风发生突变.

This study addresses the unsteady aerodynamic effects of high-speed trains encountering each other at tunnel entrances in crosswind conditions.It establishes a three-dimensional,compress-ible,and turbulent aerodynamic model of the tunnel and train that considers wind effects.The sliding mesh technique is employed to simulate the process of train encounters.The SST-o turbulence model is adopted to analyze the entire train encounter process under crosswind conditions.The study investigates the impact of crosswinds on transient pressure,train-induced wind,and flow field distribu-tion within the tunnel.The research results show that under crosswind conditions,there is a significant increase in the amplitude of aerodynamic pressure coefficient variations at the tunnel entrance during train encounters.The peak-to-peak pressure coefficient between trains upon completion of the encoun-ter under crosswind conditions is 30.6%higher compared to windless situations.Aerodynamic pres-sure experiences abrupt changes both at the beginning and completion of train encounters,with the maximum peak in aerodynamic pressure occurring near the middle of the tunnel.The size of the aero-dynamic pressure under crosswind conditions during train encounters varies with spatial positions,with the pressure variation between trains during encounters being 2.2 and 1.5 times that on the wind-ward and leeward sides of the train,respectively.Furthermore,crosswinds notably influence train wind near the tunnel entrance,with the highest wind peak on the windward side when crosswinds are present and on the leeward side when there is no crosswind,with the former being 2.04 times the lat-ter.The aerodynamic effects within the tunnel are limited in range under crosswind conditions.For in-stance,with a crosswind of 30 m/s and a train speed of 350 km/h,the aerodynamic effects within the tunnel are influenced over a range of 120 m.When train encounters commence and conclude under crosswind conditions,there is a dramatic change in flow field distribution,resulting in abrupt changes in aerodynamic pressure and train-induced wind.