A wave signature based method for the prediction of pressure transients in railway tunnels

The unsteady aerodynamic effects in railway tunnels are generally analyzed by quasi one-dimensional numerical simulations which can give the effects of the pressure waves encountered in the tunnels with a low CPU cost. In the present work, a new method for predicting the evolution of the pressure in the tunnel is presented. This method, based on the signature of the pressure waves during their propagation, requires lower computational efforts, gives results with a precision equivalent to those obtained by conventional methods, and permits to investigate more complex situations of train circulation in simple tunnel. The simulation of the tunnel length influence on the pressure changes permits to define a very short, a short and a long tunnel. The crossing of two High speed trains in tunnel is simulated with different delays in the time entry of the trains, and it is shown that the maximum pressure change in the tunnel or on the trains is function of this time shift.