Research on Influence of the Type of Cross Wind Field on the Aerodynamic Performance of a High-Speed Train

Characteristic of cross wind field, such as uniform wind and lower atmospheric boundary layer wind, have directly influence on the operation safety of high-speed train which running in cross wind environment. In order to accurately assess its effect on the train running in flat land, flow field and aerodynamic characteristics of the high speed train running at 350 km/h under different wind directions in these two types of Wind field mentioned above were simulated numerically and analyzed. The results show that, for a train running in the condition of the crosswind in flat land, aerodynamic lift, lateral force and overturning moment acting on the train increased rapidly with the wind direction angle increasing; when the train running through the lower atmospheric boundary layer, compared to an uniform wind filed, the pressure difference of the train at top, bottom and two sides were less, lateral force and overturning moment were also less, and aerodynamic lift had some uncertainty when the wind direction angle increased. Using the uniform wind for the operation safety evaluation of high-speed train which running in cross wind environment will overestimate risks the cross wind on the train operation safety, make the safety of the train too low to limit speed, thus affect the normal operation and the traffic efficiency. The lower atmospheric boundary layer wind was suggested to be used for the evaluation of the aerodynamic performance of a train.