An experimental and theoretical study of shock-wave propagation through reactive gases under conditions causing a transformation of the flow structure

Abstract

Experimental observations of the transformation of the structure of shock waves entering the discharge gap of either a transverse or decaying glow discharge are presented. It is found that the total impulse of the shock wave pressure remains constant. A variation in the speed of sound, that is, the shock wave velocity, at which total dispersion of the wave occurs is found to be nonmonotonous across the discharge gap. The times over which the wave structure keeps changing after switching off the discharge have been more accurately determined. On the basis of the obtained experimental data and earlier results, a conclusion on the mechanism of this effect has been drawn. This mechanism is related to the dispersion of disturbances making up the wave structure in a relaxing medium (such as the glow discharge plasma). On the basis of a theory of this kind of dispersion, using the experimental data, and comparing energetic and temporal characteristics of the internal states of the plasma under study and the mode of sound disturbances (which according to the experiment, are responsible for the effect), we have succeeded in determining the O2(a1Δg) state whose relaxation brings about this effect.