列車のトンネル突入時に突入側坑口から放射される圧力波の数値解析

概要

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It is well known that when a pressure wave generated by a high-speed train entering a tunnel is propagated through the tunnel and arrives at the distant tunnel exit, a micro-pressure wave is radiated from the exit portal. In addition, several pressure waves are radiated from the entrance portal when a train enters the tunnel and from the exit portal when the train leaves it. Here, the former is called a tunnel entry wave, and the latter a tunnel exit wave. Although the tunnel entry/exit wave is usually weaker than the micro-pressure wave, they could cause an environmental problem for future high-speed railways. In this study, numerical analysis is performed to clarify the phenomenon of the tunnel entry wave and predict its waveform. The numerical method is a combination of the unsteady compressible inviscid flow solver and the acoustic analogy. The numerical results show that a negative pressure pulse is radiated when the train nose enters the tunnel and a positive pressure pulse when the train tail enters. Also it is shown that the tunnel entry wave attenuates as the distance between the tunnel entrance and the observer point becomes larger but has a strong directivity in the direction of train running. The results of the numerical analysis in the cases where the entrance is unflanged and flanged are compared with those of model experiments and satisfactory agreement has been obtained.
一般社団法人日本機械学会の論文
2000-11-25