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

• Published in: Nihon Kikai Gakkai rombunshuu. B hen Vol. 60; no. 578; pp. 3402 - 3407
• Main Authors: Kage, Kazuyuki, Okubayashi, Toyoyasu, Imada, Katsutaka, Kawagoe, Shigetoshi
• Format: Journal Article
• Language: English; Japanese
• Published: The Japan Society of Mechanical Engineers 1994
• Subjects: Characteristic Method
• ISSN: 0387-5016; 1884-8346
• DOI: 10.1299/kikaib.60.3402

In this study, entry waves produced by high-speed trains which enter a tunnel with perforated hood were numerically investigated. The equations of the one-dimensional, unsteady and compressible flow with mass removal in which the area of a tunnel is dependent on the time and distance were numerically solved by the method of characteristics. The calculations were performed for tunnels with perforated hoods of which cross-sectional areas change steeply at the joint. The parameters used in the calculation are the porosity, the entrance area and the length of the perforated hood, and the speeds of the train are 200 km/h, 250 km/h and 300 km/h. The calculated results showed that compound effects of these parameters of the perforated hood on the shape and the pressure gradient with respect to time of the entry wave were nonlinear and were not monotonic. Compound effects on the entry wave were evaluated quantitatively, and the suitable conditions of the perforated hood for the reduction of the pressure gradient with respect to time of the entry wave were clarified.