Non-isentropic, inviscid linear stability analysis of compressible mixing layers

Abstract

Using non-isentropic and non-homentropic conditions, the inviscid stability characteristics for compressible mixing layers are discussed with reference to local stability criteria and extension of semi-circle theorem. Two models of non-homentropic mixing layers are used to show that exothermic process increases the temporal and spatial growth rates over those obtained in endothermic process, contradicting existing results which use isentropic assumption. Computations in the transonic regime show that an increase in Mach number enhances the growth rates. Non-asymptotical neutral loci corresponding to double and triple bifurcation points are obtained. Convective instability behaviour is observed and endothermic process is found to enhance this behaviour.