不同路堤下携沙横风对高速列车气动特性的影响

Influence of Sand-carrying Cross Wind under Different Embankments on Aerodynamic Characteristics of High Speed Trains

为研究携沙强横风在不同路堤下对高速列车气动特性的影响,建立简化的高速列车模型,采用三维、定常、不可压雷诺时均Navier-Stokes方程和标准κ-ε两方程湍流模型,数值模拟高速列车在单线路堤、双线路堤、半堑路堤的气动性能,分析列车在不同路堤倾角的流场结构,计算列车的侧力系数、升力系数、倾覆力矩与路堤倾角之间的关系。结果表明:不同类型的路堤下,在列车背风侧近地面处,都生成一个形状不规则的漩涡,漩涡的大小与路堤倾角正相关,且负压的最大值是漩涡的中心;在列车的头车处,不同路堤下的侧力系数相差很小,尤其是半堑路堤,携沙风环境下和净风环境下侧力系数基本一致,说明有沙风对半堑路堤下高速列车侧力系数的影响很小;在各个倾角下,双线路堤的倾覆力矩系数最高,半堑路堤的倾覆力矩最小。

In order to study the effect of sand-carrying strong wind under different embankments on the aerodynamic characteristics of high speed train,a simplified model of high speed train was established.Using three dimensional,steady,incompressible Navier-Stokes equation and standardκ-εtwo equation turbulence model,the high-speed train aerodynamic performances in single embankment,double embankment,half hard embankment were simulated,the flow field under different embankment inclination was analyzed.The lateral force coefficient,lift coefficient,the relationship between the over turning moment and the embankment inclination were calculated.The results show that:under different types of embankment,near the ground on the leeward side of the train,there is an irregular shape vortex,the size of the vortex is positively correlated with the embankment inclination,and the maximum negative pressure is in the center of the vortex;at the head of the train car,the lateral force coefficient under different embankment is very small,especially for half hard embankment,the lateral force coefficients under sand-carrying wind environment and netwind environment are identical basically,showing the sand-carrying wind has little effect on the high-speed train on half hard embankment;under different inclination,double embankment has the highest overturning moment coefficient,half hard embankment has the minimal overturning moment.