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In this paper the transition from convective to absolute instability in a reacting compressible mixing layer with finite rate chemistry is examined. The reaction is assumed to be one step, irreversible, and of Arrhenius type. It is shown that absolute instability can exist for moderate heat release without backflow. The effects of the temperature ratio, heat release parameter, Zeldovich number, equivalence ratio, direction of propagation of the disturbances, and the Mach number on the transition value of the velocity ratio are given. The present results are compared to those obtained from the flame sheet model for the temperature using the Lock similarity solution for the velocity profile. Finally, the structure of the wave packets produced by an impulse in the absolutely unstable flow is examined.

A model problem is proposed to investigate the steady response of a reacting, compressible laminar jet to Mach waves generated by wavy walls in a channel of finite width. The model consists of a two‐dimensional jet of fuel emerging into a stream of oxidizer which are allowed to mix and react in the presence of the Mach waves. The governing equations are taken to be the steady parabolized Navier–Stokes equations which are solved numerically. The kinetics is assumed to be a one‐step, irreversible reaction of the Arrhenius type. Two important questions on the Mach wave–flame interactions are discussed: (i) how is the flame structure altered by the presence of the Mach waves, and (ii) can the presence of the Mach waves change the efficiency of the combustion processes?

The ignition and structure of a reacting compressible mixing layer is considered using finite rate chemistry lying between two streams of reactants with different freestream speeds and temperatures. Numerical integration of the governing equations show that the structure of the reacting flow can be quite complicated depending on the magnitude of the Zeldovich number. An analysis of both the ignition a diffusion flame regimes is presented using a combination of large Zeldovich number asymptotics and numerics. This allows to analyze the behavior of these regimes as a function of the parameters of the problem.