Research on dynamical response of projectile penetrating multi-layer water targets

Penetration experiment and numerical simulation were conducted with 10-layer water targets. The space between two water targets can be adjusted from 5.5cm to 12cm. The water target was designed to flow at a constant velocity. Two different velocities of flowing water targets namely 8.2m/s and 12.6m/s were selected in the impact tests. Projectile flight trajectory, penetration location, velocity and acceleration, were recorded by two high-speed cameras and a testing system inside the projectile. Numerical simulation was used to observe internal flow field and analyze the interaction between the projectile and water targets. We have analyzed the change process of velocity and acceleration when the projectile impacts each layer. By spectrum analyzing, filtrating and integrating, overloads of projectile penetrating multi-layer water targets are gained, they are 167g and 320g. Maximum overload value obtained by Numerical simulation agrees well with the experimental result. A vacuole appears around the projectile, which greatly reduces the water resistance resulting in a slight decrease in projectile velocity when the projectile goes through 10-layer water targets.