Photogrammetry of the Shock Front Trajectories on Dipole West Shots 8, 9, 10, and 11
GENERAL ELECTRIC CO SANTA BARBARA CA SANTA BARBARA
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This report describes the photogrammetry of shock waves produced by the simultaneous detonation of two spherical 1080 lb Pentolite charges. Four experiments were carried out. In two of the experiments one of the charges was at 25 ft above the ground and the second charge at a further height of 50 ft above the first. In the other two experiments the corresponding distances were 15 ft and 30 ft. For each charge configuration, one experiment was carried out over smooth ground and another over rough ground. In each experiment photogrammetrical measurements were made of the trajectories of the primary spherical shock from the bottom charge of the Mach stem shock along the ground surface, and of the Mach stem shock produced along the ideal reflecting plane between the two charges. Comparisons of the shock strengths of the Mach stems along the ground and close to the ideal reflecting plane, indicated an energy loss in the shock front of approximately 10 over the smooth ground and of approximately 40 over the rough ground. The trajectories of the triple points formed by the junction of the primary shocks, reflected shocks and Mach stems, also show a marked difference for the rough ground compared with the smooth ground, and the smooth ground compared with the ideal reflecting plane.