Reflection of Underwater Shock Wave due to Underwater Explosion of High Explosives. 1st Report. Reflection Patterns of Underwater Shock Wave.

Abstract

We have investigated the oblique collision of two underwater shock waves in order to make an understanding of irregular reflection, espescially von Neumann reflection, of shock waves in condensed matter by both experimental and numerical techniques. The underwater shock waves used were generated by underwater explosion of high explosives in a simple assembly. Using a conventional Shadowgraph system, we took the streak and framing photographs of the collision of two underwater shock waves at different collision angles. We compared our experimental Mach-stem velocities with those obtained by Whitham's Shock-Shock theory. In the numerical technique, the Arbitary-Larangian-Eulerian method was employed for simulating the whole phenomena in detail. The simulation results demonstrated, at least qualitively, a well agreement with the experimental results. From the simulated Shadowgraphs, we can get a clearer knowledge of the conditions for the occurrence of von Neumann reflection as well as the basic characters of von Neumann reflection.