Approximating a free-field blast environment in the test section of an explosively driven conical shock tube

Abstract

This paper presents experimental data on incident overpressures and the corresponding impulses obtained in the test section of an explosively driven $$10^\circ $$ (full angle) conical shock tube. Due to the shock tube’s steel walls approximating the boundary conditions seen by a spherical sector cut out of a detonating sphere of energetic material, a 5.3-g pentolite shock tube driver charge produces peak overpressures corresponding to a free-field detonation from an 816-g sphere of pentolite. The four test section geometries investigated in this paper (open air, cylindrical, $$10^\circ $$ inscribed square frustum, and $$10^\circ $$ circumscribed square frustum) provide a variety of different time histories for the incident overpressures and impulses, with a circumscribed square frustum yielding the best approximation of the estimated blast environment that would have been produced by a free-field detonation.