Turbulent Wind Flow over a High Speed Train

Strong cross-winds may overturn trains, so an understanding of the fluid mechanics is important. To facilitate the proper estimation of the probability of a train overturning, accurate data for the aerodynamic rolling moment about the lee rail is essential. (Of course, many other parameters are required.) The flow of a turbulent cross-wind over a train moving across an embankment is complex, and difficult to model experimentally. Many experiments have been done with stationary model trains; some including turbulent flows. The aim of this work is to use such data to verify a CFD simulation with a stationary model train on an embankment. Clearly, even the ‘best’ such experiment is an approximation. However, CFD provides the ability to model the motion of the train with respect to the ground, with a turbulent cross wind, and this is the ultimate aim.