Zero-mass Pulsatile Jets for Unmanned Underwater Vehicle Maneuvering

Compact zero-mass pulsatile jet actuators are proposed for low speed maneuvering, ducking, and station keeping of small underwater vehicles. To this end, optimization of synthetic jets for maximal thrust generation is investigated. Flow field of such jets are initially dominated by vortex ring formation. Pinched-off vortices characterize the extremum impulse accumulated by the leading vortex ring in a vortex ring formation process. Relevant parameters in this process are identified to design simple and low cost zero-mass pulsatile jet actuators. Prototypes of such actuators are built for underwater maneuvering and propulsion. The actuators could be used in two ways: (i) to improve the low speed maneuvering and station keeping capabilities of traditional propeller driven underwater vehicles, (ii) and as a synthetic jet for flow control and drag reduction at higher cruising speeds.