| The aerodynamic effects induced by high-speed train passing a tunnel are more noticeable. There are lots of achievement on transient pressure and micro-pressure wave.In addition,the entering train generates impulsive pressure waves outside the tunnel,which are directly radiated from tunnel portal to the open air. We call it the tunnel entry wave and there will be the similar phenomenon when the train leaves a tunnel, which is called tunnel exit wave.These waves can vibrate and rattle structures in neighbouring building.The phenomenon occurs on Shinkansen tunnel.However,our high-speed railway is developed at a astonishing speed. As the increase of the train speed,the phenomenon will be noticeable. They constitute a potentially important hazard and a deterrent to the introduction of very high-speed operations together with micro-pressure wave.The study of the phenomenon is useful.The paper use numerical flow simulation method to investigate the fundamental characteristics and physical mechanism of tunnel entry/exit wave.The CFD model employed the techniques of sliding mesh and arbitrary connectivity to simulate the relative motion between the block of tunnel and the train.Compared with the experimental data,the results of tunnel entry wave is correct and better than the numerical result of literature.On the basis of the correct result of tunnel entry wave,the tunnel exit wave is simulated.Then the velocity dependency and the relation between the type of the train head and tunnel entry/exit wave are studied.In this paper,the fitting relations between the amplitude of pressure wave and train velocity and the effect of differnt head type on the tunnel entry/exit wave are got.In this paper,a set of numerical method and model based on symmetrical model of revolution simulating the tunnel entry/exit wave are established,which will be regarded as the theory evidence of the further study. |
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