Fluid dynamics of underwater explosions

[摘要] The detonation of an explosive in water leads to a complex set of chemical and physical phenomena. When the detonation wave reaches the surface of the explosive it reacts violently with the water, producing a shock wave propagating outwards and also a nearly spherical gaseous bubble of detonation products. The fact that the characteristic time scales of these two phenomena differ by approximately two orders of magnitude has often been exploited by utilising independent models to describe the shock and the bubble. In this thesis both the shock and the bubble are examined using a range of methods from a differential equation solver approach through to full hydrocode simulation. With the increasing use of the hydrocode approach for the underwater explosion (UNDEX) problem and the subsequent loading of a structure, then a verification and validation process is required to ensure its accuracy. In this study the capability of the hydrocode to model the shock and the bubble and also their interaction with a rigid structure and with aflexible structure, has been assessed. This has been done computationally, by using faster running purpose built codes, and also by comparison with experimental data. A familiarisation work-up of the boundary integral code for the incompressible bubble flow, which included incorporating modifications into the code in order to investigate the pathlines swept out by the particles in the fluid during the expansion and collapse of the bubble. The boundary integral code was also used to provide a comparison with the Kelvin impulse method with respect to the computation of the zones of explosion bubble collapse direction in a shallow water environment. The validation and verification work carried out and the comparisons of the various computational approaches, make this multifaceted study a useful reference for research workers in the field of UNDEX phenomena.

[发布机构] University:University of Birmingham;Department:School of Mathematics

[关键词] Q Science;QA Mathematics