Research on the aerodynamic characteristics of high-speed train equipped with aerodynamic braking plate under crosswind

This study investigates the aerodynamic characteristics and braking performance of the next-generation high-speed train equipped with an aerodynamic braking plate (ABP) under crosswind conditions. The aerodynamic coefficients and flow field distribution characteristics during aerodynamic braking are simulated and calculated under varying crosswind speeds, wind angles, and train speeds. These simulations reference the streamlined design of CN-III 8-unit group train and incorporate the butterfly-type ABP and conventional layout scheme. Utilizing k−ω Shear Stress Transport (SST) turbulence model, the research analysed the changes in aerodynamic coefficients and flow field distribution for different side wind speeds, wind angles, and train speeds. The results reveal that the aerodynamic drag coefficient of the high-speed train with an ABP follows a cosine curve with the crosswind angle, peaking at a wind angle of 60°. The difference in aerodynamic coefficients between the high-speed train equipped with an ABP and the prototype train increases with crosswind speed, with the most significant changes observed in the head car. The wind angle notably impacts the formation and evolution of multiscale separation vortices on the leeward side of the train. Additionally, there is significant airflow interference before and after the longitudinal neighbouring ABPs on the roof, attributed to the boundary layer effect and bypassing flow. The aerodynamic drag coefficient of the high-speed train operating in a crosswind condition is a function of the wind-car speed ratio and the wind angle, with the drag coefficient being only related to the wind-car speed ratio when the crosswind angle is 90°.