The outer boundary of the non-equilibrium region of the Prandtl-Meyer expansion fan in an ideal dissociating gas

Abstract

An approximate method for the explicit numerical calculation of the outer boundary of the non-equilibrium region in the Prandtl-Meyer expansion fan of an ideal dissociating gas has been presented. Solution for the lowest order approximation was carried out for a particular initial state: degree of dissociation = 0.52427, dimensionless temperature = 0.06, dimensionless velocity = 0.74276, dimensionless density = 10 to the -7. Curves showing the shape of the outer boundary and the variation of the state and motion variables along this outer boundary are presented. The results obtained using this approximation are generally in agreement with those to be expected along the outer boundary between the frozen and equilibrium wave heads. Also, as expected, the lowest order approximation fails to maintain accuracy at angular locations of greater than about four degrees into the expansion fan.