Abstract
The velocity of the flow over the roof of the train running in a tunnel is higher than that in an open section. While the flow velocity in the tunnel predicted by one-dimensional simulation is 1.2 times higher than the train running speed, the measured flow velocity in a tunnel is about 1.3 times higher than the train running speed. Therefore, three-dimensional incompressible Reynolds Averaged Navier-Stokes Simulation (RANS) of the flow over the roof of the train running in the tunnel was conducted in order to investigate the effects of the boundary layer developing along the train on the flow velocity. The surface roughness was added to the bottom of the train to simulate the equipment installed under the car body, and its effects on the flow over the roof were investigated. In addition, the simulation of the flow over the roof with the pantograph shields was carried out. The flow velocity over the roof with the pantograph shields was compared to that over the flat roof.
