横风桥隧区域列车突出隧道时的瞬态气动特性  

Transient Aerodynamic Characteristics of Train Exiting from Bridge Tunnel Area Under Cross Wind

作　　者：毛军[1] 韩晨煜 陈明杲 MAO Jun;HAN Chenyu;CHEN Minggao(School of Civil Engineering,Beijing Jiaotong University,Beijing 100044,China)

机构地区：[1]北京交通大学土木建筑工程学院,北京100044

出　　处：《华南理工大学学报（自然科学版）》2023年第2期54-64,共11页Journal of South China University of Technology(Natural Science Edition)

基　　金：国家自然科学基金面上项目(52172336)。

摘　　要：基于横风作用下高速列车流场的非定常特性,建立了横风-列车-桥隧模型进行仿真计算,并通过1∶8列车动模型试验验证数值方法的准确性。随后研究横风条件下列车突出隧道时,隧道内外瞬态气动压力、气动荷载变化及流场特性,揭示了横风-列车-隧道之间的相互作用机理。研究结果表明:随着横风风速的增大,压力逐渐减小,但压力随时间的变化规律相似;横风对隧道出口处及隧道外监测点处的压力梯度有明显的影响,对于隧道内的监测点几乎没有影响;随着横风风速增大,隧道外背风侧正压峰值随风速增大略有减小,迎风侧正压峰值基本保持不变,背风侧负压峰值减小速率大于迎风侧;横风对列车突出隧道运行过程的压力波动影响有限,在横风风速为20 m/s时,隧道外界流场影响隧道内气动压力的范围不超过20 m。同种横风条件下,迎风侧、背风侧监测点处压力时程变化规律不相同,压力梯度峰值出现的位置也不同,且位于列车同侧越靠近地面的监测点处压力峰值及压力梯度峰值绝对值越大;横风下,气流经过车-桥系统时,在桥底部、列车背风侧顶部及底部发生明显的流动分离现象,导致隧道外车体两侧的压差大于隧道内车体两侧压差。In this paper,a cross-wind-train-bridge-tunnel model was established to conduct simulation calculation based on the unsteady characteristics of flow field under cross-wind action of high-speed trains.The accuracy of the numerical method was verified by 1∶8 dynamic model test.Then,the transient aerodynamic pressure,aerodynamic load changes and flow field characteristics inside and outside the tunnel were studied when the train broke out of the tunnel under cross-wind conditions,so as to reveal the interaction mechanism between cross-wind,train,bridge and tunnel.The results show that the pressure decreases gradually with the increase of cross wind speed,and the change law of pressure with time is similar.The cross wind has an obvious effect on the pressure gradient at the exit of the tunnel and outside the tunnel,but has almost no effect on the measuring point inside the tunnel.With the increase of cross wind speed,the peak value of the positive pressure on the leeward side outside the tunnel decreases slightly with the increase of wind speed,while the peak value of the positive pressure on the windward side basically remains unchanged.And the decrease rate of the peak value of the negative pressure on the leeward side is greater than that on the windward side.The cross wind has limited influence on the pressure fluctuation of train protruded tunnel.When the cross wind speed is 20 m/s,the scope of influence of the external flow field on the pneumatic pressure in the tunnel is less than 20 m.Under the same cross-wind condition,the pressure time-history variation rules at the measuring points on the windward side and the leeward side are different,and the position of the peak value of the pressure gradient is also different.The closer the measuring points on the same side of the train are to the ground,the greater the peak value and the absolute value of the peak value of the pressure gradient are.Under cross wind,when the airflow passes through the vehicle-bridge system,obvious flow separation occurs at the bottom

关 键 词：横风 高速列车 桥隧区域 瞬变压力 流场 

分 类 号：U25[交通运输工程—道路与铁道工程]