Reflection of Underwater Shock Wave due to Underwater Explosion of High Explosives : 2nd Report, Curvatures of the vNR and the Transition Criteria from MR to vNR

Abstract

We have previously reported our studies on the phenomenon of von Neumann reflection of underwater shock waves by experimental and numerical techniques. In this paper, as a further supplement to the previous report, we mainly made our efforts to investigate the change trend of the Mach stem curvature in von Neumann reflection of underwater shock wave. We presented a theoretical analysis model on describing the change of Mach stem curvature on the basis of Whitham's Ray-shock theory. It has been shown that our analytical results agree quite well both experimental and numerical results. Finally, we also presented the theoretical prediction on the domains and transition boundaries between regular reflection, Mach reflection and von Neumann reflection, of underwater shock wave by the above theory, as well as the comparison with those from the experiment and numerical calculation.