Numerical study of the effect of the tunnel hood on micro-pressure wave for increasing high-speed train operation speed

The effects of the tunnel hood on the micro-pressure wave were investigated by the numerical simulations of high-speed train with increasing the operating speed from 260 km/h to 400 km/h. Reduced 4 cars of the Korean Train eXpress (KTX) and the shortened tunnel along the Kyeongbu high-speed railway were used to focus on the entry compression wave and to sufficiently prevent the expansion wave reflected from the tunnel exit. As the operating speed increased, the intensity of the compression wave, compression wave gradient and micro-pressure wave increased regardless of the tunnel hood, but the magnitude was decreased due to the effects of the tunnel hood. However, although the tunnel hood was considered, the intensity of the micro-pressure wave for the speed of 400 km/h exceeded the regulation of South Korea. It was found that the micro-pressure wave can be mitigated by decreasing the slant angle of the tunnel hood.