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.