Comparison of different configurations of aerodynamic braking plate on the flow around a high-speed train

End of vehicle streamlined head was selected as the installation location, and aerodynamic behavior of trains with and without braking plates was compared to analyze the formation of the braking force and the evolution of the flow field. An IDDES method based on the SST κ–ω turbulence model was used to investigate the unsteady flow, and the numerical algorithm was validated. Results show that the train aerodynamic drag was significantly increased by opening the braking plates, especially when several braking plates were arranged separately in series on each train car. Furthermore, the effect of the plate installed on the tail car was superior to that of the braking plate on the head car, when only a single braking plate was used. It was also found that both the maximum value of the slipstream and negative pressure close to the braking plate depend on the position and size of the braking plate. The flow field around the lower part of the train was only slightly affected by opening the braking plates, and pairs of vortices over the train appeared when the braking plates were opened, significantly affected both size and position of vortices in the train wake.