NUMERICAL STUDY OF UNDERWATER EXPLOSION NEAR AIR-WATER SURFACE
近水面水下爆炸的数值研究

The strong blast-wave generated from an intense underwater explosion interactsstrongly with the air-watcrinterfacet forming refractive shock wave and reflective rarefactionwave.These waves are regular initially,but soon develops into irregular pattern. Accompa-nied with this interaction between the blast wave and the free surface,a spray dome formsand develops into a huge hollow water-column. These complex physical features put greatdemands on numerical computation that the numerics should be able to capture severe free-surface distortion and complex wave pattern. In the present work,we apply the level-setfunction approach to resolve the free-surface motion,the distortion of the surface and theinteractions between air-water interface and blast wave can be successfully captured.Thepresent method is simple and second-order accurate. It provides an effective means forsolving the problems involving free-surface motion.