Study on Micro-Pressure Waves Discharged from the Exit of a Model Tunnel

초록

Micro-pressure waves always occur at tunnel exit when a high-speed train is moving inside the train tunnel, which are also called impulse waves. The air around train nose is compressed and compression waves are induced. Micro-pressure waves are discharged at train tunnel exit as compression wave propagated outside of tunnel exit. Micro-pressure waves are weak-strength pressure waves, which lead to noise and other environmental problems. In order to efficiently control micro-pressure waves at train tunnel exit, numerical studies on investigating generation and propagation of impulse waves were carried out. A 3-D symmetric model tunnel was simulated at different operating conditions. Different Mach number of compression waves was varied to initialize different magnitudes of micro-pressure waves at tunnel entrance. In addition, effects of wave length were also investigated on the generation of impulse waves. Two monitor points were installed at tunnel exit to record pressure histories as impulse waves moved through two locations. The detailed magnitude and characteristics of micro-pressure waves were obtained in the present studies.