Large Eddy Simulations of a Typical European High-Speed Train Inside Tunnels

This article presents our results of external aerodynamics, obtained with Large Eddy Simulations (LES), about a typical European passenger-stock inside tunnels. The focal points are the aerodynamic forces and their typical frequencies applied to the tail. Two train lengths and three tunnels are employed in the study to model the conditions of double and single-track bores. Owing to the relatively high numerical cost associated with LES for external train aerodynamics we could only afford sufficient spatial grid resolution on our shortest train. The flow simulations confirm the existence of coherent structures alongside the body that give rise to continuously propagating pressure disturbances. These disturbances with a relatively small amplitude and high spatial frequency cannot affect the ride comfort. Still, they are found to influence the flow separation about the tail, which is regarded as one of the candidate mechanisms to impair the ride comfort and running stability.