Abstract
The propagation of a compression wave generated by a high-speed train entering into a tunnel and the reduction effect of a micro-pressure wave by a portal hood at a tunnel exit have been studied with field measurements, model experiments, and numerical simulations. First, we conduct field measurement the propagation of a compression wave in a tunnel. Also we numerically simulate the propagation by solving the 1D compressible Navier-Stokes equations with an unsteady turbulence effect. The result shows that the pressure gradient of the compression wave increases as it propagates in a long tunnel for the train speed exceeding 500km/h, and thus the micro-pressure wave, whose strength is proportional to the pressure gradient of the compression wave, should be reduced. In this study, we focus on a portal hood with a porous wall as a countermeasure against the micro-pressure wave and study its effect with an experiment using a 1/34-scale model. The experimental result shows that the micro-pressure wave can be reduced by the porous hood placed at the tunnel exit, and that its reduction effect increases for a longer porous hood. Both the numerical and the experimental results agree well with the field measurement data.
