Some aspects of shock-wave research

A few examples are given of shock wave phenomena on earth and in space to provide some useful background material. The major portion of the paper is devoted to a specific shock wave research problem, namely, pseudostationary oblique shock wave reflections in perfect and imperfect gases. Consideration is given to what has been achieved to date by using two and three shock theory to predict what type of reflection results when a planar shock wave M sub s, in a shock tube, collides with a sharp compressive wedge of angle, Theta sub w. Experimental (interferometric and other optical) data are presented in M sub s, Theta sub w-plots for argon, nitrogen, oxygen, air, carbon-dioxide, Freon 12 and sulfurhexafluoride, in order to check the validity of the analytically predicted regions and transition lines of the four types of reflection. Some disagreements are noted and discussed. Our interferometric isopycnic data are also compared with state of the art computational results from a solution of the inviscid Euler equations using a CRAY I computer. Good agreement was obtained, yet, it would be important to obtain new data by solving the Navier Stokes equations, as well as the rate equations for imperfect gas excitations, in order to judge the improvement obtained with real flow interferograms.