~ _— <2 2.3 TASK UNIT 13 PROGRAMS(DOD) 2.3.1 Program 1, Blast and Shock Measurements The broad objective of Program 1 was to measure and Study the blast forces transmitted through the various media of the earth. In the main, measurements were obtained in air by means of Wiancko and mechanical self-recording pickups. Those obtained within the water were taken by means of tourmaline, Wiancko, strain gauge, and ball-crusher pickups. A few earth measurements were made, using Wiancko accelerometers. Successful measurements contributing to the fulfillment of the objectives were made by 10 out of 12 projects. Of the two _unsuccessful projects, one failure was brought about by the extremely low yield’ The other project failure was brought about by the scheduled time of firing which imposed unfavorable light conditions for photography. Manyinteresting and valuable records were obtained during the shot series." These records were interpreted in the field and will be reexamined subsequently at the home laboratories of the varic .~ project agencigs. The following tentstive conclusions are based on preliminary data and, ther="":°, are subject to change upos a more careful study of the records. 1. Ine o'r shock pressure-time trac: s obtained at close-in ground ranges were distorted. 2, Altnough distorted air shock wave forms were noted, no serious peak pressure dis- crepancies (as compared to the 2W Operation Tumbler-Snapper composite free air pressures) were noted. 3, Dynamic air pressures were obtained that were higher than those predicted by the Rankine-Hugoniot relations applied to air. The pressure discrepancies were probably a result of sand and/or water loading of the shock wave. 4, Within the ranges instrumented (7500 to 20,000 ft), underwater shock pressures were not appreciably larger than the air pressure at the corresponding distance. Approximately equal peak-pressure-inducing signals were transmitted through the earth and air, and these induced peak pressures were approximately equa! to those of the air shock wave at corresponding distances. . 5. The heights of the water waves induced within the Bikini lagoon can be approximated by the empirical relation H.R = 2.25w'? (¢/180)'? : p