分离式公铁双层桥面桥梁-列车-风屏障系统气动效应风洞试验研究

为探究侧风作用下分离式公铁双层桥面桥梁上、下桥面间气动干扰效应对列车气动效应的影响,在无风屏障和设置风屏障两种情况下,分别针对单独铁路桥和标准间隔高度下的公铁双层桥面桥梁,通过大比例尺节段模型风洞试验测试了列车的气动力系数以及铁路桥面轨道上方的风速剖面变化规律。为了进一步探究公铁双层桥面间隔高度对列车气动效应的影响,测试了多种间隔高度下列车气动力系数以及铁路桥面轨道上方的风速剖面变化规律。结果表明,公铁双层桥面间气动干扰效应对列车气动效应有一定的影响,间隔高度的改变会引起铁路桥面风速剖面以及列车气动力系数的变化,对比分析可知,无风屏障时间隔高度仅需满足铁路桥梁基本建筑限界即可,设置风屏障后,当间隔高度≥15m时,铁路桥面风速剖面以及迎风侧轨道处列车气动力变化趋于平缓。

Study on aerodynamic effects of the separate-type highway-railway double-deck bridge-vehicle-wind screen system by wind tunnel tests

The influence of aerodynamic interaction between the upper deck and the lower deck of separate-type highway-railway double-deck bridges on the aerodynamic effects of vehicles under cross wind is explored. For the separate railway bridge and highway-railway double-deck bridges with the standard height interval, the aerodynamic coefficients of vehicles and the variation of wind profile above the orbit of railway bridge decks, with and without wind screens, are measured by large scale section model wind tunnel tests. Various height intervals have been taken into account to further explore the influence of the height interval on the aerodynamic effects of vehicles. The result shows that the aerodynamic interaction between highway-railway double decks will influence the aerodynamic effects of vehicles, and the wind profile above railway bridge deck and aerodynamic coefficients of vehicles will change with the height intervals. According to the comparison analysis, the height interval is only needed to satisfy the basic structure gauge for railway bridges without wind screen. When the height interval is more than 15m, the change of wind profile above the orbit of railway bridge deck and the aerodynamic forces of vehicles located on the upwind side gets flat when wind screens are used.