列车编成辆数对高速列车横风气动特性影响的数值分析

对3～8辆编组列车以350km· h-1速度运行时,不同速度横风作用下的气动特性进行仿真研究,并建立列车的阻力系数与列车编组辆数之间的无量纲关系.研究结果表明:对3辆车编组列车的气动特性分析不能取代对其他编成辆数列车的几动特性分析；不同编成辆数列车阻力系数随着横风风速的增加而增大,3辆车编组列车的阻力系数不超过8辆车编组的列车的一半；列车的侧向力系数和倾覆力矩系数随着列车编成辆数的增加而减小；列车编成辆数对头车的阻力系数、升力系数、侧向力系数和倾覆力矩系数影响较小,但是对尾车的影响较大；头车的侧向力系数和倾覆力矩系数明显高于尾车和中间车,尾车的倾覆力矩系数最大值不超过0.4,而头车的最大可达0.7；由于头车的气动安全性比其他位置车辆的低,用头车的气动安全性评估整个列车的气动安全性会偏于保守,但合理、可行.

Numerical Analysis on the Influence of Train Formation on the Aerodynamic Characteristics of High-Speed Trains under Crosswind

Simulation was carried out on the aerodynamic characteristics of train consisting of 3~8 cars running at the speed of 350 km·h-1 in crosswind with different velocity.Dimensionless relationship was established between the drag coefficient of train and the number of train formation.Results show that the analysis on the aerodynamic characteristics of train that consists of 3 cars can’t replace that of train consisting of other number of cars.The drag coefficient of different train formation increases with the increase of crosswind velocity,and the drag coefficient of train that consists of 3 cars is lower than half of that of 8 cars.The lateral force coefficient and overturning moment coefficient of train decrease with the increasing number of cars that compose a train.The number of cars has less influence on the drag coefficient,lift coefficient,lateral force coefficient and overturning moment coefficient of head car,but it has greater influence on those of tail car.The lateral force coefficient and overturning moment coefficient of head car are obviously higher than those of intermediate car and tail car.The maximum overturning moment coefficient of tail car is less than 0.4,while that of head car reaches 0.7.As the aerodynamic safety of head car is lower than that of other cars,estimating the aerodynamic safety of the whole train based on the aerodynamic safety of head car tends to be conservative,but it’s reasonable and feasible.