Numerical simulation of underwater burst events using sharp interface capturing methods

A methodology for conducting numerical simulations of underwater burst events is described in this paper. A numerical model for compressible two-phase flow is formulated, with the gas phase modeled as a mixture of thermally-perfect gases and the liquid phase (water) modeled using an extended Tait equation that accounts for thermal effects. Cavitation effects are modeled using a mass-generation rate law proportional to the difference between the local pressure and the vapor pressure of water. Sharp capturing of discontinuities (shocks, contact waves, phase interfaces) is facilitated through the use of several schemes, including the van Leer TVD scheme, a tangent hyperbola interface capturing (THINC) method, and a boundary variation diminishing (BVD) scheme, which combines the TVD and THINC reconstructions to minimize numerical dissipation. An immersed-boundary method is utilized to embed complex terrain into the simulation domain. Results are presented for several 2D / 3D cases in which an underwater explosion is idealized as an expanding volume of high-pressure gas.