LES study of the impact of the wake structures on the aerodynamics of a simplified ICE2 train subjected to a side wind

Until recently, experimental studies and numerical simulations of the flow around trains in side winds have focused on measuring the main integral quantities, such as the aerodynamic forces and moments, but not much on understanding the flow structures. Chiu and Squire [1] experimentally found that at low yaw angles (up to 40°) the flow is similar to the steady slender body flow, in which pairs of steady line vortices are emerging from the separation lines on the lee-side face to form the wake structures. When the side-wind yaw angle increases above 60°, the flow changes from that associated with a slender body to unsteady vortex shedding. However, the mechanism of this transition between these two types of flows and its effect on the aerodynamic forces have not been investigated in detail.