Active attenuation of tunnel pressure wave with negative pressure gradient generated by positive pressure.

When a high speed train enters into a long tunnel, a tunnel pressure wave occurs. When the tunnel pressure wave propagates and approaches the tunnel exit, low frequency noise radiates from the exit and causes vibration of residential dwellings. Based on a model experimental system, this paper proposes an original way to attenuate positive pressure gradient of tunnel pressure wave with a negative pressure gradient generated by positive pressure and discusses how to realize it. Computational simulation indicated that attenuation of the positive gradient of tunnel pressure wave due to the negative pressure gradient of positive pressure is effective.