On the effect of rail-end slope in train aerodynamics under crosswind

Abstract

Railway track models with sloped subgrade ends, are commonly used in studies of train. In the present work, the effect of subgrade-end slope under a yaw angle of 30° was investigated by delayed detached eddy simulation (DDES) using one-eighth-scale train and single-track rail models. The obtained results were validated with wind tunnel tests. Time-averaged aerodynamic coefficients, pressure distribution, and flow field around the train were analysed and compared in three cases with different subgrade-end slopes. The results show that, the lift force of three cars is reduced with increasing subgrade-end slope, while the side force is found to be increased with increasing slope; the overturning moment of head and middle car decrease but which of tail increase. The extreme values occur in the case of 60°. Furthermore, the subgrade-end slope gives a variable impact on pressure distribution and flow pattern in different regions. This work has guiding significance for the selection of rail models in the subsequent train aerodynamic studies.