To decrease the effect of compression wave, the numerical simulation of a three-dimensional
viscous flow induced by a high-speed train entering tunnels with a shaft was made. In the simulation, the
Navier-Stokes equations, describing three-dimensional viscous, compressible, isentropic and nonstationary
flows, were taken as the control equations, the cell-centered finite volume scheme for numerical integration
of the Navier-Stokes equations was used for space discretization, and the preconditioned second-order
accurate backward difference was adopted in time discretization. In addition, the walls and floor of a tunnel
were described with wall functions. The calculated result agrees with the oversea experimental one.The
research shows that the shaft can decrease air pressure in tunnels, and its section area and position have a
great effect on the pressure.