As a high-speed train enters a tunnel, a compression wave is generated ahead of the train and propagates along the tunnel. At the exit of the tunnel, part of the compression wave is reflected backward as an expansion wave and propagates toward the tunnel entrance. The expansion wave interferes with the moving train and consequently causes pressure transients in the tunnel. On the other hand, part of the compression wave emerges from the tunnel exit and becomes an impulsive wave, which radiates toward the surroundings, creating an impulsive noise. The objective of this work is to investigate the appropriate silencer configuration for reducing this impulsive noise. Five kinds of silencers were installed at a shock tube exit, and their effects on the impulsive noise were investigated numerically and experimentally. Two-dimensional unsteady conservation equations were solved by means of a PLM. Experiments were carried out using a shock tube with an open end. As a result, the effect of silencer configuration on noise reduction was clarified, and it was found that a suitable choice of the silencer could reduce the strength of the impulsive wave by about 25 %.
Reduction of impulsive noise caused by unsteady compression wave
Dämpfung der Schallabstrahlung der Druckwellen von Eisenbahnzügen bei der Tunnelausfahrt
JSME International Journal, Series B (Fluids and Thermal Engineering) ; 40 , 2 ; 223-229
1997
7 Seiten, 14 Bilder, 1 Tabelle, 7 Quellen
Aufsatz (Zeitschrift)
Englisch
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