Effect of compressibility on laminar flame speed and its stabilizing effect on Darrieus-Landau instability of a premixed flame front

The compressibility effect on a premixed flame front is investigated for small Mach numbers Ma in terms of M² expansions. We extend the method of matched asymptotic expansions to O(Ma²) in which a flame front consists of he reaction and the preheat zones, By an asymptotic analysis of the reaction zone, we establish a rapid decrease of the laminar flame speed S-_L with Ma and a volumetric heat loss, of compressibility origin, brought by the pressure variation in the heat-conduction equation, which has been gone neglected in the zero-Mach-number limit. Together with O(Ma²) effect, this dramatic decrease in S-_L brings in stabilization of the Darrieus-Landau instability, the linear instability of a plane flame front.