Mitigating crosswind effect on high-speed trains by active blowing method : a comparative study

Abstract

To reduce the crosswind effect on high-speed trains, in this paper, by using the Improved Delayed Detached Eddy Simulation (IDDES) method and the SST (Formula presented.) turbulence model, a novel blowing measure is studied and compared by considering different positions of blowing slots on the train surface. The concerned blowing positions on the train surface include the top position (Top); windward side (WWS): the upper position (WU), middle position (WM), and lower position (WL); and leeward side (LWS): the upper position (LU), middle position (LM), and lower position (LL). The results show that in regard to the rolling moment coefficient around the leeward rail, CMxlee, the mitigation effect with LM for the head car is the largest, and the mitigation effect with WL for the middle car and tail car is superior to other cases. The corresponding drop percentages are 18.5%, 21.7%, and 30.8% for the head car, middle car, and tail car, respectively. The flow structures indicate that the blowing positions on the lower half of WWS and upper half of LWS would form a protective air gap to weaken the impact of coming flows and delay the vortex separation on LWS, and thus the train aerodynamic performance is improved.