SCALED TRAIN TUNNEL SIMULATOR FOR WEAK SHOCK-WAVE GENERATION EXPERIMENT

A scaled train tunnel simulator has been constructed for investigating weak shock waves which are generated in a long tunnel when a high-spe ed train enters it. The simulator consists of a driver section which c an launch a 50 g and 18 mm diam piston (model train) at up to 120 m/s (430 km/h) and a 40 mm diameter and 25 m long tube. The entire tunnel simulator is inclined by 8 degrees so that the decrease of the piston speed is minimized. The performance of the driver section is analyzed and a simple algebraic formulation is obtained. Mainly due to aerodyna mic drag force, the piston speed is decreased by at most 10% through t he tube. The effect of the decrease of the piston speed on shock wave generation processes is found to be negligible. Using this scaled trai n tunnel simulator, the overpressure of shock waves which is generated by a high-speed train is well reproduced by laboratory experiments.