采用三维、非定常、不可压缩雷诺时均N-S方程和Realizableκ-ε双方程湍流模型,对以350km/h车速等速交会、350-0km/h不等速交会和350km/h单车运行时的3车编组高速列车气动性能进行了模拟,对比分析了车体表面和流场中的压力和速度变化.数值算法经过验证,与试验波形吻合,幅值相差不超过5%.结果表明,从列车交会侧车底到车顶,表面压力先增大后减小,峰值出现在车体凸起部位,其相对于交会侧最小压力系数区域,变化幅值可达1.76-2倍.第一个正压波峰对于距离轨面高度更为敏感,两负波幅值减小相对较小,幅值变化不超过30%.列车尾流造成的列车风较大,对空间高度十分敏感,随高度增加,列车风速度迅速减小,主要集中在半车高以下区域.列车周围不存在障碍时,列车周围流场具有时空互换性,差异主要体现在具有强非定常性流场的风挡和尾部区域.
Based on the three-dimensional unsteady compressible Reynolds-averaged N-S equation and the Realizableκ-εdual equation turbulence model,the aerodynamic performances of the three marshalling high-speed trains,running at speed of 350km/h,passing each other at the same speed(350km/h)or passing each other at the different speed(35 0km/h and 0km/h),are simulated.The pressure and velocity change of the train surface and in the flow field are compared and analyzed.Numerical algorithm is verified with experiments in this paper.The wave profile obtained in numerical simulation agrees well with the one of experiments,and the difference between them is below 5%.From the bottom to the top of the train intersection,the surface pressure increases first and then decreases.The maximum of pressure change appears at the raised part of train body and can reach to 1.76-2times of the minimum pressure.The first positive pressure wave is more sensitive to the distance between the monitoring point and the rail surface.The decrease of two negative pressure waves is relatively small,which is no more than 30%.The gust induced by the wake is the most dramatic,which is very sensitive to the height.The velocity of gust rapidly decreases with the increase of height.The train gust is mainly concentrated in the area of the half car height.When train running in open air,the flow field around the train has space-time interchangeability and the difference is mainly reflected in strong unsteady flow around windshield and tail car.