抄録
A compression wave is generated ahead of a high-speed train, while entering a tunnel. This compression wave propagates to the tunnel exit and spouts as a micro pressure wave, which causes an exploding sound. In order to estimate the magnitude correctly, the mechanism of the attenuation and distortion of a compression wavefront propagating along a tunnel must be understood and the experimental information on these phenomena is required. An experimental investigation is carried out to clarify the attenuation and distortion of the propagating compression wave in a very long tube. From the results, it is confirmed that the maximum pressure gradient of the wave along a very long tube depends on the detail wavefront as well as the initial maximum pressure gradient.
