Detonation shock dynamics and comparisons with direct numerical simulation

Comparisons between direct numerical simulation (DNS) of detonation and det onation shock dynamics (DSD) is made. The theory of DSD defines the motion of the detonation shock in terms of the intrinsic geometry of the shock sur face, in particular for condensed phase explosives the shock normal velocit y, D-n, the normal acceleration, (D) over dot(n), and the total curvature, kappa. In particular, the properties of three intrinsic front evolution law s are studied and compared. These are (i) constant speed detonation (Huygen s construction), (ii) curvature-dependent speed propagation (D-n-kappa rela tion) and (iii) curvature- and speed-dependent acceleration ((D) over dot(n )-D-n-kappa relation). We show that it is possible to measure shock dynamic s directly from simulation of the reactive Euler equations and that subsequ ent numerical solution of the intrinsic partial differential equation for t he shock motion (e.g. a (D) over dot(n)-D-n-kappa relation) reproduces the computed shock motion with high precision.