Exploring Flow Structures Around a Simplified ICE2 Train Subjected to a 30 Degree Side Wind Using LES

Artikel i vetenskaplig tidskrift, 2009

Large-eddy simulation (LES) is conducted to investigate the flow around a simplified ICE2 train under side wind conditions at 30° yaw angle. The Reynolds number based on the height of the train and the free stream velocity is 200000. Two computations on two different meshes with different numbers of nodes are made to check the effect of the mesh resolution on the results. The fine and the coarse meshes give similar results meaning that the results are mesh independent. The results are also verified against available experimental data. Good agreement is obtained between the LES results and the experimental data. The LES results show that two flow regimes exist in the wake. The first flow regime consists of steady vortex lines in the upper part of the wake flow. It changes into unsteady shedding after a distance of about five train heights from their onset on the surface of the train. The second flow regime is the unsteady movement of the lower part of the wake vortices. They attach and detach from the surface of the train in a regular fashion. The time-averaged flow and the instantaneous flow around the ICE2 train at 30° yaw angle are explored.