Numerical Study of Compression Waves Produced by High-Speed Trains Entering a Tunnel : Effects of Shape of Hood

In this study, compression waves produced by trains which enter a hooded tunnel at high speed were numerically investigated. Equations of the one-dimensional, unsteady and compressible flow in which the area of a tube is dependent on the time and the distance were numerically solved by the method of characteristics. The calculations were performed for tunnels with various hoods of different shapes in cases in which the speed of the train was 200 km/h or 300 km/h, and the effects of the shape of the hood on the shape and the strength of compression waves were quantitatively clarified. The results show that the pressure gradient of compression waves is greatly affected by the shape of the hood.