Underfloor Flow Measurements of 1:50 Generic High Speed Train Configurations for Different Ground Conditions in a Water Towing Tank

Abstract

Two-component high-speed particle image velocimetry of the underfloor flow of three different 1:50 generic high-speed train models hauled through a water towing tank over a smooth, a rough and a ground with sleepers at a speed of 4 m/s (Re = 0.25 Mio) were conducted. It was found that any additional irregularities at the underbody increase the velocities, the velocity fluctuations and the velocity gradients at the ground which increases the chance of ballast flight. Therefore, it is concluded that a smooth underbody can lower the risk of ballast flight. The results were compared to full-scale measurements. The main characteristics of the underfloor flow are captured in the water towing tank for downscaled train models.