强横风下青藏线客车在不同高度桥梁上的气动性能分析

Aerodynamic performance of passenger train on different height of bridge of Qinghai-Tibet railway line under strong cross wind

采用数值模拟方法,在模拟自然风和均匀风风速分别为30m/s的情况下,研究不同高度桥梁上列车受到的横向力和侧滚力矩,导出了桥梁上车辆的横向力系数和侧滚力矩系数的表达式。计算结果表明:桥高为30m时,采用模拟自然风计算得到的横向力和临界倾覆点处侧滚力矩比采用均匀风得到的计算结果分别大约58%和63%,且桥梁越高,计算结果差别越大;车体周围的流场与速度矢量分布方式相似,但采用模拟自然风时,车体的表面压力最大值和车体周围的速度最大值分别为1.14kPa和67.6m/s,远大于采用均匀风时的最大值0.82kPa和58.8m/s;车辆受到的横向力、侧滚力矩基本上与车辆形心处的风速的平方成正比;车辆的横向力系数和侧滚力矩系数均与桥梁的高度呈指数关系,当量横向力系数为0.974,当量车体重心处的侧滚力矩系数为0.082,当量临界倾覆点处侧滚力矩系数为0.592。

Numerical simulation method was used to research the aerodynamic side force and overturning moment of the train in different heights of bridges when the simulated natural side wind speed and uniform side wind speed were 30 m/s. The coefficient expressions of side force and overturning moment are induced. The results show that when the bridge is 30 meters high the side force and overturning moment using simulated natural wind are about 58% and 63% larger than that when using uniform wind, respectively, and that the higher of the bridges, the larger difference of the results are. The fluent structure and speed vector distribution are similar but the maximum pressure on the surface and maximum wind speed about the train are 1.14 kPa and 67.6 m/s, respectively, when using simulated natural wind while they are 0.82 kPa and 58.8m/s, respectively, when using uniform wind. The calculation results of aerodynamic forces in different heights of bridge show that the side force and overturning moment are proportional to the square of wind speed at the height of train center. The coefficients of side force and overturning moment are submitted to exponential distribution according to the height of the bridge, and equivalent coefficients of side force, overturning moment in weight center of train and overturning moment in critical overturning point are 0.974, 0.082 and 0.592, respectively.