AN AERODYNAMIC DESIGN OF HIGH-SPEED TRAIN FOR REDUCING FLOW-INDUCED VIBRATION IN TUNNEL

As the maximum speed of high-speed trains in Japan increases, flow-induced vibration of trains in tunnels has become a subject of discussion. Running tests showed that coherent structures exist in the space between the tunnel wall and the train. We conducted numerical simulations to explain the mechanism of generating these flow structures. The computations revealed that vortices occur around the bottom of the train. These vortices develop from the head toward the tail. An unsteady aerodynamic force is generated on the side of the train when these vortices pass. By taking the above result into consideration, we proposed new designs for the train bottom. Wind tunnel experiments confirmed that the new designs effectively reduce the aerodynamic force.