NUMERICAL SIMULATION OF UNDERWATER EXPLOSIVE BUBBLE USING LAGRANGIAN PPM

摘要

Underwater shock waves produced by underwater explosion of high explosives (HE) has been studied, as a manufacturing process of metals, for many years. Underwater explosion (UNDEX) experimental investigation is very expensive. On the other hand it is almost impossible to study the early development of the explosion, since the current measuring devices cannot bear the ultra high pressure (about 500kbar) generated near the charge. When an explosion occurs under water, the resulting energy release creates an expanding gaseous volume (i.e., the so-called bubble) that contains explosion products. The main difference between underwater explosions and explosions in air arises from the dynamics of this bubble. Expansion and collapse of this energetic bubble generates damage mechanisms in water which occurs over a wide range of time scales. High speed photography can be used to observe the bubble behavior. However, their visual results are not clear enough to describe the internal dynamics of the gaseous products of explosion.