强侧风下桥上高速列车倾覆稳定性及最优风障高度的研究

Overturning stability of a high-speed train running on a bridge and optimal height of wind barriers under strong crosswind

基于计算流体动力学理论,采用数值模拟的方法计算了高速列车通过双线简支箱梁桥时的气动力系数,考虑了轨道超高引起的列车风攻角、列车位于桥梁的横向位置、风障高度以及风偏角等因素的影响。根据列车运行于不同平曲线线路时的受力特点定义了列车倾覆系数,并参考有关标准设定了倾覆系数的容许值。在侧风风速为30 m/s情况下,计算了列车以不同速度通过设置有不同高度风障的桥梁时的倾覆系数,并据此选择了最优风障高度。计算结果表明:迎风侧线路上列车气动力系数比背风侧线路大,风障相对较低时升力系数随列车风攻角增大而增大;对迎风侧轮轨接触轴线和背风侧轮轨接触轴线的倾覆系数随车速和风障高度的变化规律均相反,最优风障高度由对背风侧轴线的倾覆系数决定;当列车处于迎风侧线路上时需设置的风障高度均比处于背风侧线路时高,即迎风侧线路是双线桥梁风障高度设置的控制线路;对于主导风向稳定的弯道,侧风从弯道内侧吹向列车时,最优风障高度随车速的增大而增大,从弯道外侧吹向列车时则与之相反;对于主导风向不稳定的弯道,应取侧风从外侧和内侧吹入时需设置风障的较大者。

Based on the theory of computational fluid dynamics,the aerodynamic coefficients of a high-speed train running on a simply supported box-girder bridge with double lines were computed with numerical simulation,and the effects of the train attack angle caused by track super elevation,the lateral position of the train on the bridge,the height of the wind barriers and the wind incidence angle were considered.The overturning coefficient of the train was defined according to the load-bearing characteristics of the train running on various horizontal curve lines,and the allowable value of the overturning coefficient was set with reference to related codes.Under the condition that the crosswind velocity was 30m/s,the overturning coefficients of the train at various velocities running on the bridge with wind barriers of various heights were calculated,and the optimal heights of wind barriers were selected accordingly.The results showed that the aerodynamic coefficients when the train is running on windward line are larger than those on leeward line,the lift force coefficients increase with increase in wind attack angle of the train when wind barriers are relatively lower; the overturning coefficients for windward wheel/rail contact axis and leeward wheel/rail contact axis vary oppositely with increase in both running velocity and height of wind barriers,and the optimal height of wind barriers is selected according to the overturning coefficients of leeward axes; the required heights of wind barriers when the train is running on windward line are higher than those on leeward line,so the windward line is the control line of a double-line bridge for selecting the height of wind barriers; to a curve line,when the dominant wind direction is stable,the optimal height of wind barriers increase with increase in nyning velocity if the crosswind blows from the inside of the curve,the rule is opposite if the crosswind blows from the outside of the curve; to a curve hne,when the wind direction is not stable,the height of wind barriers should be the larger one of the required heights if wind blows from both the inside and the outside of the curve.