Flow Induced by the Emission of a Comparatively Strong Shock Wave from an Open-End of a Tube

When the shock wave propagating along the straight circular tube reaches at the open end, the spherical shock wave is generated by the emission of a shock wave from an open end and the unsteady jet is formed near the open end behind the spherical shock wave. The shock strength of spherical shock wave is dependent on the shock Mach number in the tube, and it attenuates with propagation distance from the open end. In this study, the flow induced by the emission of a comparatively strong shock wave from an open end of a tube with the infinity flange is analyzed numerically by the TVD method. As a result, it is concluded that the asymptotic position and diameter of Mack disk of unsteady jet are equal to the steady jet corresponding the pressure ratio. In addition, the relationship between strength of spherical shock wave and Mach number of incident shock wave is clarified from viewpoints of the characteristics of attenuation and directivity for the spherical shock wave.