Study on the formation process of entry compression waves generated by a high-speed train entering tunnel

초록

An entry compression wave is the first of the successive waves produced as a high-speed train enters a tunnel. This wave propagates at the speed of sound and can cause certain aero-acoustic problems, which have long been the concern of researchers. The pressure intensity and the amplitude of this particular wave vary according to the train speed and tunnel characteristics. Hence, to understand the effect of train speed on formation process of the compression wave, a computational investigation using a commercial computational fluid dynamics (CFD) solver FLUENT 17.1 has been performed. The train at a given speed is moved as a rigid body and the stationary mesh is updated using the dynamic meshing update techniques. The numerical scheme for this specific problem has been validated against a reduced scale experimental setup. Further, five different train speeds have been studied for an axisymmetric train entering a uniform cross-section tunnel portal. The changes in pressure have been recorded inside the tunnel wall at two distinct points and the consequent flow physics has been presented in detail using pressure and velocity contours. Finally, using the current CFD results an empirical correlation between the train speed and the pressure intensity of the entry compression wave has been established."