Simulation analysis and validation on aerodynamics of tunnels on high speed railways

With the increase of train speed, the issue of tunnel aerodynamics becomes more important. A simulation platform based on CFX is established to fulfill simulation calculation of tunnel aerodynamics for 300km/h high speed railways, with emphasis laid on studying the changing rules of compression wave and pressure transient on tunnel wall while the train enters tunnel as well as micro-pressure wave at tunnel portal with speed increase. The simulation results are then compared with actual measuring result. It is shown that the simulation result is basically consistent with laboratory measurement thus the finite element simulation could be applied in practice; amplitude of the initial compression wave will slightly decrease with the increase of tunnel length and the amplitude bandwidth will gradually increase. When the train speed is no more than 300km/h, the micro-pressure is basically proportional to cube of speed and when the train speed is more than 300km/h, the micro-pressure will see drastic increase and it is proportional to 6.5th power of speed.