THE REFRACTION OF SHOCK-WAVE OVER A SLOW-FAST GAS INTERFACE

This paper presents a numerical simulation of the shock wave refractio n over an interface of two different gases. Harten-Yee upwind TVD sche me is used and an approximate Riemann solver has been developed specia lly for this problem in which the interface of the two gases can be tr eated without any peculiar consideration. Some experimental data have been obtained for the refraction of a planar shock at the air/CO2 and air/He interfaces. The refraction and reflection of the shock wave as well as the flow field around it are visualized by using double exposu re holographic interferometry. The numerical simulation results were c ompared with the experimental results, good agreement was obtained. Ba sed on the one-dimensional piston theory, the conditions for both BPR (Irregular Refraction of the Bound Precursors) into FPR (Free Precurso r Refraction) and FNR (Free Precursor von Neumann Irregular Refraction ) into TNR (Twin von Neumann Refraction) transitions are analysed. The crater of the gaseous interface near the boundary is also discussed i n this work. Copyright (C) 1996 Elsevier Science Ltd