Experimental Research On Aerodynamics In Tunnels With High Speed Trains

With the development of the speed-up of the railway, the effects of the aerodynamics become more and more important when high-speed train trains entering a tunnel. The tunnel hood is one of the measurements with which the effects of the aerodynamics in tunnels would he alleviated. The more and more application promotes a continuous development of the tunnel hoods.In order to make the tunnel hoods have a better effect on the respect of alleviating the aerodynamics in tunnels, the theory of the generating and propagation of the compression wave in tunnels should be research and the effects of all kinds of tunnel hoods on the compression wave should be analyzed. The analysis of the compression wave and the effects of the tunnel hoods by experimental method is the purpose of this paper.This paper conclude the history and present situation of the research of the compression wave home and abroad; summarize the forms dimensions of the railway tunnels and tunnel hoods abroad; discuss the physics model and mathematics model of the air flow when high-speed train running in a tunnel and introduce the compulation method of the pressure in tunnels briefly. Similarity criterion is established according to a l/70lh moving model facility. Compared with situations of without tunnel hoods and 3 different kinds of tunnel hoods, the relationships of the max pressure, the gradient of the pressure and the velocity of the train are attained and the propagation process of the compression waves in tunnel is verified. The good effects of the tunnel hoods on alleviating the aerodynamics problems in tunnels can be obtained. The dimensions of the tunnel hoods and the connection of the tunnel hood and tunnel have a great effect on the alleviation.