横风作用下公铁同层桥上汽车-列车的气动特性风洞试验研究

Wind tunnel tests on aerodynamic characteristics of vehicles on same-storey highway and rail bridge under crosswind

横风作用下桥上车辆的运行安全性和舒适性已得到越来越多的关注。准确了解桥上车辆气动特性是评估强风作用下行车安全性和舒适性的基本前提。由于公铁同层桥上汽车和列车存在显著的相互气动影响,使得车辆气动特性更为复杂。本文以集装箱卡车和CRH2高速列车为例,通过风洞试验对某大跨公铁同层桥上车辆气动特性开展研究。试验结果表明,公铁同层桥上列车与公路车辆之间的空气动力干扰随着列车(轨道上游,轨道下游)和公路车辆(迎风侧,背风侧)的位置以及轨道上放置的列车数量而变化;列车对上游的公路车辆气动力影响较小,对下游的公路车辆影响较大,且公路车辆侧力系数受列车干扰效应最为显著;桥上公路车辆仅对列车有限宽度的表面压力分布有影响,对该范围内的列车升力系数影响最大,列车的其他气动力则主要受相邻列车气动干扰的影响。

In recent years,the safety and comfort of road vehicles driving on bridges under crosswinds have attracted more attention due to frequent occurrences of wind-induced disasters.This study focuses on a container truck and CRH2 high-speed train as research targets.Wind tunnel experiments are performed to investigate shielding effects of trains on aerodynamic characteristics of trucks.The results show that aerodynamic interference between trains and trucks varies with positions of trains(upstream,downstream)and trucks(upwind,downwind)and numbers of trains.To summarize,whether the train is upstream or downstream of tracks has basically no effect on aerodynamic forces,other than moments,of a truck driving on windward sides of bridges(upwind).In contrast,the presence of trains on the bridge deck has a significant impact on aerodynamic characteristics of a truck driving on leeward sides(downwind)at the same time.The best shielding effect on lateral forces of trucks occurs when the train is located downstream of tracks.Finally,the pressure measuring system shows that only lift forces on trains are affected by trucks,while other forces and moments are primarily affected by adjacent trains.