Calculation of Muzzle Blast Flowfields

Abstract

The muzzle blast field generated by a gun-launched high-velocity projectile is characterized by a highly underexpanded supersonic exhaust plume, which terminates at a strong shock (the Mach disk), an expanding front of exhaust gases (the contact surface), and an expanding, nearly spherical outer shock (the blast wave). The present study is directed toward theoretical description of the inviscid gas dynamics of the blast field. The rioted features are discussed in terms of well-establis hed theories for spherical blast waves with variable energy release and for steady underexpanded plumes, from which their interaction can be qualitatively described. To obtain a quantitative representation, a finite difference solution is developed for the unsteady compressible flow between the Mach disk and the blast wave, assuming spherical symmetry. The results obtained are in good agreement with experimental measurements of the motion of the blast wave, the contact surface and Mach disk for a 3200 fps round fired from an M16 rifle. a B C d E