高速列车气动阻力地板效应数值研究

针对CRH2型动车组外形，在2种1∶25缩比模型风洞试验基础上，展开基于数值模拟的明线情况高速列车不同地板试验条件阻力测量影响研究。通过与风洞试验结果对比，确定数值方法的可靠性；通过数值模拟风洞壁地板、固定地板、移动地板下高速列车流场分布与阻力变化情况表明，不同试验地板的地面效应对高速列车阻力测量结果影响很大，移动地板模拟效果最佳，固定地板与风洞壁地板阻力测量值小于移动地板情况，且差距随车身长度的增加而增加，很难模拟真实列车运行的流场；通过深入分析不同地板条件的影响机理，为高速列车不同地板条件风洞阻力测量结果提供参考意见。

Numerical study of ground effects on high speed train aerodynamic drag

Based on wind tunnel tests of aerodynamic drag on two kinds of 1/25th scale CRH2 models, research of aerodynamic drag with different experimental ground planes was carried out by numerical simulation. The reliability of the numerical methods was verified by comparing the results of simulation and tests. By analyzing the variation of the flow field and resistance distribution on the train body with the usage of the wind tunnel wall, the stationary ground plane, and the moving ground plane in simulation, it is found that: ground effects of different planes have a great influence on the drag measurement of the high speed train; the moving ground plane gives the best simulation performance; the results of drag computed with the other two ground planes are less than that with the moving plane and the difference increases with the increase of the body length, therefore, it is almost impossible to simulate the flow field of the real train operation. Finally the mechanism of influence by ground planes is analyzed and references are provided for drag measurement of high speed train on different ground planes.