Experimental Investigation of a Body Water Entry with a Water Jet Cavitator

This paper reports an experimental investigation on the flow of a water entry cavity formed with a water jet cavitator. To investigate the formation characteristics, systematic water entry experiments were conducted in a water tank under different water jet rates, entry velocities, entry angles, and nozzle diameters. The formation mechanism of the water entry cavity was also analyzed. Results indicate that before the model impacts the water surface for water entry with a water jet cavitator, a gas bubble is created, and its width increases as the model approaches the water surface. Moreover, the length of the water jet gradually reduces to zero due to the increase in the static pressure of the water. The formation of the cavity is directly correlated with the location of the stagnation point moving downstream from the far field of the water jet to the exit of the water jet nozzle with the increasing entry depth. The dominant parameter is the momentum ratio of the water jet and quiescent water.