1998 Volume 41 Issue 4 Pages 814-821
Experimental studies on weak shock wave attenuation in high-speed train tunnels were conducted using a 1 / 250-scaled train tunnel simulator and a shock tube. Three kinds of porous / perforated walls installed in the test section of the simulator near its exit were examined. Installing aluminum foam or porous plastic on the wall clearly decreased the pressure gradient of the wave front. The processes of the shock wave attenuation were visualized by holographic interferometer. A significant decrease in the overpressure was obtained by installing perforations along the simulator wall. However, with the short perforation section of 0.5m, the pressure gradient of the shock wave remained steep. Through the series of the experiment and theoretical consideration, it is found that the length of the perforated / porous section is one of the most essential parameters to effectively attenuate the shock wave.