A Numerical Study of the Aerodynamic Characteristics of a High-Speed Train under the Effect of Crosswind and Rain

The performances of high-speed trains in the presence of coupling effects with crosswind and rain have attracted great attention in recent years. The objective of the present paper was to investigate the aerodynamic characteristics of a high-speed train under such conditions in the framework of an Eulerian-Lagrangian approach. An aerodynamic model of a high-speed train was first set up, and the side force coefficient obtained from numerical simulation was compared with that provided by wind tunnel experiments to verify the accuracy of the approach. Then, the effects of the yaw angle, the resultant wind speed, and the rainfall rate on aerodynamic coefficients were analyzed. The results indicate that the aerodynamic coefficients grow almost linearly with the rainfall rate, and increase with a decrease in the resultant wind speed. Due to the impact of raindrops on the train surface and the airflow, the pressure coefficients of windward and leeward side of the train become larger with the increase of the rainfall rate. Raindrops can accelerate the airflow and suppress the vortices detachment. Moreover, the flow velocity in regions surrounding the train increases with an increase in the rainfall rate.