On the effect of crosswinds on the slipstream of a freight train and associated effects

Abstract

When a train moves through the air, a region of air moves along with it at approximately the same speed: this region of air is known as the ‘slipstream’. Numerical simulations were conducted in order to simulate the slipstream around a model-scale freight train when subjected to crosswinds with two different yaw angles; 10° and 30°. The results were compared to a previous slipstream study without a crosswind. The velocities on the windward side of the train for each case are mostly lower than the crosswind speed due to the flow stagnation on the side of the train. In general, crosswind velocities are lower than those in the no-crosswind case. On the leeward side, velocities from the 30° crosswind case remain higher than train speed for more than two metres from train side. Peak instantaneous velocities showed strong dependence on yaw angle and position from train side as well as exhibiting superficial comparison to full-scale data. Velocities were used as inputs to a spring-mass-damper model which modelled human responses to wind gusts. The effect of a crosswind on the train's slipstream significantly increased the likelihood of a person becoming unsteadied while standing on the leeward side of the train.