Internal Detonations

Abstract

Detonations inside structures present a number of complicating factors. Multiple reflections from walls, floors and ceilings interact and enhance the overpressure. In a structure which has few internal walls or partitions such as a parking garage, the blast wave reflects from the floor and ceiling. Mach stems form on both surfaces. As the triple points grow away from each surface, the two Mach stems will combine. At that time the expansion of the blast wave is essentially cylindrical and the effective yield of the blast wave is nearly four times that of the original detonation. Figure 17.1 is taken at a time when the blast wave has propagated more than five effective heights of burst. The burst took place at R = 0 at a height of burst of zero between a floor and ceiling separated by 3 m. The Mach stems shown at the shock front are the second Mach stems caused by reflection of the reflected shocks.