The growth and decay of sonic waves in dissociating gases

Abstract

The propagation of sonic waves through dissociating gases has been discussed. The velocity of propagation is determined and it is found that the weak disturbances in dissociating gases propagate with the effective velocity of sound relative to the gas flow. The fundamental differential equations governing the growth and decay of sonic waves are obtained and solved for various forms of wavefronts. It is concluded that if the sonic wave is a compressive wave of order 1, then it terminates into a shock wave after a critical time tc which has been determined. But on the other hand if it is a rarefaction wave, it will continuously decay and will be damped out ultimately. It is also shown that the dissociative effects are to decrease the critical time tc. In the case of a rarefaction wave the effects of dissociation will cause more rapid damping effects. © 1976 with the authors.