Abstract: The air pressure wave pattern in a railway tunnel when a high-speed train passes through is quite complicated. This is because the pressure wave in the tunnel is a superposition of the entrance pressure wave, which is produced by the train entering the tunnel and is moved back and forth inside the tunnel, and the pressure perturbation at each particular points of interest produced by the train passing by. From the point of view for strength design of train bodies and security of train operation, the altitudes of the maximum positive air pressure and negative air pressure in tunnel, and the appearance positions of these air pressure peaks should be understood. The dynamic process of high speed trains passing through railway tunnels are simulated and analyzed by means of 3D numerical analysis of computational fluid dynamics equations. Superposition relation of the entrance pressure waves and pressure perturbation produced by the passing train is proved from the calculation results. The possible locations of the maximum positive and negative pressures peaks inside the tunnel are obtained. The predictive formula of the maximum pressure peak values as a function of train speed is derived. This study can potentially be used as a reference for aerodynamically designing of high-speed trains and high-speed railways tunnels.

Key words: high speed train, pressure pulse, simulation analysis, tunnels