新幹線後尾部のトンネル突入による車両振動の解析

The generation of compression and expansion waves is one of the biggest issues faced while designing high-speed trains. These waves are generated at the moment the nose and tail of the train enter the tunnel. The vibration of high-speed trains running in a tunnel is known to be greater than that of trains running in an open area. This vibration has been explained by the asymmetrical flow separation and vortex shedding from the surface of the train. In this paper, the vibration might be related to the expansion wave that is generated as the tail of the train enters the tunnel. In this study, a combined simulation of flow and vibration was developed based on computational fluid dynamics and vibration dynamics. The results showed that the pressure difference at the sides of the train caused by the expansion waves passed from the tail to the nose with a time lag. The accuracy of the proposed method was discussed by comparing the results of a real high-speed train. Consequently, we demonstrated that aerodynamic force was strongly associated with lateral vibration when the train entered the tunnel.