Study of Aerodynamic Drag/Pressure Transients Induced by High-Speed Train Passing in a Tunnel

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1.The first project was carried out to develop an open-ended shock tube with a fast opening gate valve instead of a diaphragm. The results show that the opening of a gate valve decreases with an increasing the initial pressure of the actuating chamber.2.The strength, maximum rate of pressure rise and length of wavefront are strongly dependent on the initial pressue of the actuating chamber and the opening speed of a gate valve.3.The second project was carried out to investigate experimentally the transition of unsteady boundary layr. The experimental data were compared with the theoretical results for a weak shock wave.4.It was found that the laminar-to-turbulent transition in unsteady boundary layr flow, which describes the density profiles at strength of the initial compression wave from 9 kPa, exists.5.The final project was carried out to investigate experimentally and numerically the pressure transients in the high-speed train/tunnel systems and the formation mechanism of pressure transients. The experimental data were compared with the numerical results by the characteristic method and TVD differential method.6.It was shown that the strength of the pressure transients are strongly dependent on the velocity of each train and the the formation mechanism of pressure transients is clarified.