Hydrodynamic ram effect driven by a hollow spherical hypervelocity projectile

This paper presents two numerical simulations of hypervelocity impacts of a spherical hollow aluminium projectile (V0 = 2940 m/s) onto a hollow, cylindrical containment with water filling, serving as representative filling substance for fluids. The paper focuses on the following subject:(A) Numerical investigation of the unsteady, kinetic energy penetration induced flow field inside the containment.(B) Differences of the processes with and without the containment. A central requirement for this paper, is to adapt ANSYS/AUTODYN-3D solvers capabilities to compute the hypervelocity impact induced flow of the three material aggregates a) solid (aluminium, polycarbonate) b) liquid (water) c) gaseous (air) in the computational model, to bring up the gaseous cavity behind the penetrating hollow sphere. The evolution of the growth of the air cavity (diameter) in the water phase is a main result of this study. The air cavity growth is fed by the inflow of atmospheric air from outside the containment.