Mitigation of Explosion Bubble Pulsation Caused by the Deep Underwater Detonation of a Tapered Charge
Abstract
The dynamics of the explosion bubble growth and collapse due to the underwater detonation of a 5.3-m-long tapered charge containing 454 kg of TNT are examined calculationally. The burst was 305 m below the sea surface in deep water. The calculational method, using a coupled Eulerian-Lagrangian finite-difference hydrodynamics computer code, was made credible by successfully calculating the explosion bubble dynamics of spherical TNT charges detonated at the same depth of burst. Results show the tapered charge explosion bubble exhibits characteristics that are very similar to an equal-weight spherical charge over the first bubble period. This implies that bubble pulses will be produced by tapered charge detonations at this depth and deeper. The bubble pulses emitted by deep tapered charge detonations are not characteristic of the underwater nuclear detonation that these charges are designed to simulate. In fact, for conventional charges, bubble reloading of models is severe, and can lead to their unplanned collapse. Three methods of tapered charge bubble pulse mitigation were examined: (1) injection of propellant gas into the bubble to prevent/cushion collapse, (2) dissipation of bubble energy through enhancement of turbulence at the first minimum by creating an asymmetric bubble, and (3) using an explosive that produces condensible/soluble detonation products, thereby allowing more rapid transfer of bubble energy to the water and preventing the creation of a substantial bubble pulse. Results show that 2 and 3 are promising methods of bubble pulse mitigation. Additional work must be done to quantify the effectiveness of these methods and produce specific test designs.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 31, 1980
- Accession Number
- ADA107804
Entities
People
- J. M. Thomsen
- S. F. Ruhl