Water entry system

Abstract

A water entry system increases the drag of an underwater vehicle by disrupting the cavity that forms during high-speed transit of the vehicle through the water. A series of inlet ports are positioned in regions of the vehicle where pressure stagnation occurs during transit. Flow passages connect these inlets to outlet ports at regions of lower pressure. Pressure differences cause jets to flow in the respective passages. The jets produce a high flow rate normal to the original cavity boundary. The jets serve to increase drag in at least two manners. In one case, a flow jet normal to the cavity interface broadens the cavity to increase drag and slow the vehicle. In a second case, a jet can cause waves on the cavity interface to break down the stable cavity. As a result, the vehicle surface is wetted, producing skin friction drag and slowing vehicle.