Explosively Generated Water Cavities

In the mid 1960 s, B. G. Craig at the Los Alamos National Laboratory performed experiments designed to characterize the formation of water waves from explosives detonated near the water surface. He reported observing the formation of ejecta water jets above and jets or roots below the expanding gas cavity. This was unexpected and a scientific mystery which remained unsolved until it was finally modeled using the NOBEL code in December of 2002. 

In the early 1980 s, the hypervelocity impact (1.25 to 6 kilometers/sec) of projectiles into water was studied at the University of Arizona by Gault and Sonett. They observed quite different behavior of the water cavity as it expanded when the atmospheric pressure was reduced from one to a tenth atmosphere. Above about a third of an atmosphere, a jet of water formed above the expanding cavity and a jet or root emerged below the bottom of the cavity. 

The NOBEL code has been used to model the experimental geometries of Sonett and of Craig. The experimental observations were reproduced as the atmospheric pressure was varied as described in reference 14. 

Projectile and Exploding Bridge Wire Generated Cavities 

In the early 1980 s, experiments were being performed at the University of Arizona to simulate asteroid impacts in the ocean. The hypervelocity impact (1.25 to 6 kilometers/sec) of various solid spherical projectiles (Pyrex or Aluminum) with water was performed by Gault and SonettTheir observations were similar to those previously observed by Craig. While the water cavity was expanding, an ejecta jet was formed at the axis above the water plume and a jet or root emerged along the axis below the cavity. The water cavity appeared to close and descend into deeper water. 

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Explosively generated water cavities modeled using NOBEL are described in Chapter... 

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