Real Surface (Non-Ideal) Effects on Nuclear Explosion Airblast from PRISCILLA-Type Events, Part 1: Comparison and Evaluation of Ideal and Non-Ideal Airblast from PRISCILLA Computations; and Part 2: SHARC Hydrocode Calculations of the PRISCILLA Event (Phase 1)

An extensive analysis of the 24 June 1957 PRISCILLA 36.6 KT nuclear event at a 700 ft height of burst over a desert surface at the Nevada Test Site is presented, along with early time results from three hydrocode computations simulating that event. The computations included simulations of ideal, actual desert, and grassland surface. The desert computation produced reasonable agreement with most of the data from PRISCILiA. However, the precursor was not as advanced as that observed. The grassland computation produced a strong and persistent precursor. There was a mismatch between arrival times used for developing the thermal layers and those actually computed, indicating the need for coupling of the SHARC hydrocode and the THRML thermal layer codes. Both desert and grassland cases produced enhanced dynamic pressure impulses that attained a maximum of a factor of 8 above ideal in the range of concern to Army equipment Overturning computations for comhat vehicles showed ranges for overturning were extended by factors as large as 1.8 over ideal ground ranges. These effects have implications for Army tactics and doctrine and show the need for continuing non-ideal computations for other surfaces, yields, and heights of burst. Recommendations for further studies are included. (MM)