Computations and Experiments of Shallow Depth Explosion Plumes

Abstract

Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. REPORT DATE AUG 19962. REPORT TYPE 3. DATES COVERED 00-00-1996 to 00-00-1996 FOREWORDThis report was prepared in support of the Water Barrier Ship Self-Defense Concept, managed by C. E. Higdon of the Naval Surface Warfare Center, Dahlgren Division (NSWCDD), Dahlgren, Virginia, Code G42. Under the sponsorship of the Office of Naval Research (ONR), Arlington, Virginia, the Center is developing technology that has the potential to be very effective in defending Navy platforms against high speed low flying antiship missiles (ASMs). The concept uses a wall of water to provide a low cost, universal terminal defense system for ships. The wall of water or water barrier is formed from the shallow detonations of multiple underwater explosives to protect the ship from attacking ASMs. This concept can be employed to slow or stop debris and warhead fragments from missiles killed at very short range to preclude significant damage to the defending ship. Furthermore, the barrier would defeat the fuzing and structure of ASMs that have penetrated the inner self-defense layer.The main thrust of this report is to provide validations of a hydrodynamics computer code for predicting explosion plume behavior. The results of experiments conducted at NSWC Carderock Division, Bethesda, Maryland, in May 1993, at a quarry in Arvonia, Virginia in August 1994, and at the Briar Point facility of the Aberdeen Proving Grounds in June 1994, are used for the validation studies.The research in this paper related to the Water Barrier Ship Self-Defense Concept was supported by D. Siegal (ONR, Code 351). The basic research required for the development of the computational method and some of the theory presented was supported, in part, by R. Lau (ONR, Code 311) and the NSWC Independent Research (IR) fund.In addition to the sponsors of this research, the authors would like to acknowledge the work of J. Connor (NSWC Indian Head (IH) 9540A) for providing plume height measurements and underwater bubble and plume profiles; K. Boulais, J. Choe, and K. Erwin (NSWCDD, B42) for providing the microwave data measurements; and L. Lipton (NSWCIH 450) for providing the density probe data. We also thank S. L. Drinnon (NSWCDD, B44) for assisting in preparing t...

Coupled hydrodynamic-acoustic modeling of sound generated by impacting cylindrical water jets

“…In this paper, a computational model based on a generalized hydrodynamics theory designed to treat violent liquid collisions is used. This method has been successfully used to calculate the collision of two liquid cylinders, 31 shallow water plume formation, 32 and explosive cratering in water-covered sand. 33 The generalized hydrodynamic model is based on a system of conservation laws subject to a one-sided density constraint.…”

Generalized Hydrodynamics with Viscoplasticity for Channeling in Saturated Sand

“…For example, in a shallow depth explosion (which does not vent), a plume of water is ejected upward above the bubble as the bubble attains its maximum volume. At the same time, another jet of water flows downward from the plume through the bubble as it begins its collapse [4,5,6].…”

“…Manuscript approved December 16, 1999. In previous work [5,6,[10][11][12][13], the authors and colleagues have developed a computational capability for free surface flows in an incompressible fluid based on a generalized hydrodynamics model. The code BUB2D has been used to simulate two-dimensional (2-D) or axially symmetric problems, and BUB3D simulates fully three-dimensional (3-D) flows.…”

“…While these codes have been applied to many flow situations, the most relevant to surf-zone explosive cratering problems are the examples of shallow depth explosions in a single incompressible species (water) [5,6]. The presence of saturated sand complicates the situation, primarily due to its dual dynamical properties.…”

Model Validations and Predictions for Water Barrier Defense

“…In a recent work [2], observations of a large set of experiments were used to improve a set of empirical relations for modeling underwater explosion bubbles in an incompressible medium (water). While such relations were derived and reported as long ago as 1948 by Cole [3] these approximations were not valid for very shallow depths due to simplifying assumptions that were made.…”