Unsteady response of chain-branching premixed-flames to pressure waves

Motivated by some recent experimental results that are incompatible with the standard one-step model, we present an analytical study of the unsteady response of flames to acoustic waves in the framework of a simple two-step chemistry model, using conditions that are appropriate to approximately describe lean methane-air flames. The calculated response functions are qualitatively different from those obtained with the standard one-step model. The results are sufficiently encouraging to suggest that the analysis should be extended in the near future to more detailed kinetics schemes.