Cavity dynamics in hydrodynamic ram analysis of confined containers under ballistic impacts

In this paper, high-speed impacting different size water-filled containers by projectiles have been performed experimentally, particular attention is given to characterizing the container confinement effects on the cavity characteristics induced by regular projectiles impacting into the confined containers. Experimental results indicate that the confinement effect on the cavity evolution is mainly reflected in the influences on the maximum cavity radius and the average cavity wall velocity. An analytical cavity model based on the principle of energy conservation was developed to describe the cavity dynamics in high-speed impacting these “non-infinite” containers. Furthermore, the hydrodynamic pressure acting on the container wall induced by cavity expansion and the critical size of the container in presence of constraint effects were theoretically analyzed. The objective of presented work is to reveal the problem of hydrodynamic pressures acting on the container wall caused by cavity expansion in a Hydrodynamic ram event, and to provide the theoretical basis for studying the nature of Hydrodynamic ram caused by cavity expansion along the trajectory. Good agreements were observed between analytical results and experimental observations. •Container size has an obvious inhibition effect on the cavity evolution.•A cavity model that has the container confinement effect was developed.•Hydrodynamic pressure acting on the container wall was analyzed theoretically.•A model of the critical container size in presence of constraint effects was proposed.