Investigation of Bubble Collapse and Water Jet Induced by Underwater Explosion in a Rectangular Tube

Introduction

The rapid release of energy beneath the surface of water results in movement of the surrounding water, especially on the side of free surface. This can be realized using chemical and nuclear explosions, electric discharge, or pulsed laser focusing. By carefully setting the depth of explosion in a confined tube, a pulsed water jet can be effectively generated at the exit of the tube. The laser-induced liquid jet has been studied in biology and medicine [1]. This water jet is also important in volcanology to investigate explosive volcano eruptions that are driven by expanding gas bubbles [2]. In these applications, the bubble is generated in a confined space as in a pipe or a channel. Shallow and deep underwater explosions have been heavily investigated experimentally and numerically for decades. However the behavior of collapsing bubble and water jet in a confined space have not much been studied so far. The motivation of this study is to investigate the behavior of collapsing bubble and water jet formation in a narrow tube with a rectangular cross-section by underwater explosion. Special attentions are paid on the repeatability, so that the collected data can be used to validate numerical models for these compressibility dominated two-phase flows.