Simulations of converging shocks in water

Numerical simulations of weak shocks in water traveling through a convergent geometry were performed. The convergent geometry is surrounded by an elastic solid, which is deformed by the fluid, thereby, generating elastic waves in the solid, which in turn affect the liquid, thus creating a coupled fluid-structure problem. Here, we use the Overture suit, which is a code for solving partial differential equations on curvilinear overlapping grids using adaptive mesh refinement. In particular, we use a multiphysics solver to solve the fluid-structure problem. The Euler equations with a stiffened equation of state are used in the fluid domain and the linear elasticity equations are used in the solid domain. The solutions at the interface between the fluid and the solid are matched using continuity of normal velocities and forces. Preliminary results indicate that the wave speed of the material has a large influence on the behavior of the converging shock. The numerical simulations are also compared to schlieren photographs and pressure measurements obtained from experiments. Results can enhance the design of marine structures with convergent sections subjected to dynamic loading events. [Work supported by ONR.]