Theory of weakly unstable multi-dimensional detonation

An asymptotic analysis of the multi-dimensional detonation instability has been developed in the limit that the ratio q of the reaction heat release o ver the enthalpy at the leading shock is much smaller than unity. The leadi ng order solution corresponds to a wave equation describing the dynamics of the inert shock wave. By considering the next order destabilizing effects related to the heat release fluctuation and the non-uniform distribution of the stationary solution, an expression of the dispersion relation, which i s valid in the vicinity of the bifurcation limits, has been obtained. The p resent work extends our previous analysis (He 1996a) in the Newtonian limit to general situation for q much less than 1. It is found that the dispersi on relation so determined is identical to that presented in (He 1996a), whi ch was obtained in the Newtonian limit and q much less than 1 by carrying o ut an asymptotic analysis to the second order. The theoretical results for the growth rate and the bifurcation Limits agree well with the numerical so lutions of the exact linear instability problem. The physical mechanisms in volved in the cellular detonations have been discussed.