Nonlinear waves in gases

Abstract

The method of characteristic perturbation is used to analyze the main features of small amplitude waves generated by a planar piston-like surface in a perfectly conducting gas. The nonlinear effects and the effect of a magnetic field on the wave motion are fully taken into account in the analysis. The trajectory of the wave, the particle path in the physical plane, and the speed of propagation for a weak shock wave are calculated. From the calculation, it is clear that the speed of propagation for a weak shock wave is the average of the characteristic speeds on both its sides. It is also found, in the case of central expansion waves, that the gas velocity is not influenced by the magnetic field, whereas the pressure and the density are lowered in comparison to what they would be in the absence of a magnetic field. Copyright © 1996 Elsevier Science Ltd.