Study of the fl ow around railway embankment of different heights with and without trains

The present work mainly focuses on the evolution of the airflow passing embankments of different heights, with and without trains. Using the delayed detached-eddy simulation (DDES) method, the effects on the velocity and acceleration of the airflow caused by the embankments’ upstream slope were studied using a set of embankments with different heights. The aerodynamic loads experienced by each car of the train, on both the windward and leeward rails, were calculated and the effects of different embankments examined. To distinguish how the geometry of embankments affected the flow patterns, distributions of streamline, velocity and the vortices formed around the head car and embankment are shown. The differences in pressure distribution on central loops of each car caused by the different embankment heights were analyzed at a yaw angle of 19.8°. Using the wind speed at 4 ​m above the actual rails and the reference at 10 ​m above the ground, the effect of wind speed on the aerodynamic forces and moments of the train, independent of the embankments’ height, can be obtained. This method has the potential to simplify the calculations needed to evaluate the safety of trains running on different embankment heights in strong wind environments. © 2020 Elsevier Ltd