A Bio-Inspired Delayed Stall Propulsor for Enhanced Thrust and Reduced Noise

The proposed Phase II effort develops a bio-inspired delay stall propulsor (BDSP) concept employing delayed stall unsteady lift enhancement to increase the lift on propeller blades without adding any complexity to the propulsor. The approach is simple tomanufacture, rugged, and easy to retrofit into existing designs. In Phase I, preliminary 2D simulations demonstrating concept feasibility have shown at least a 36% reduction in rotational speed at constant thrust and at least an estimated 4 db reductionin the total radiated acoustic power. The proposed Phase II effort will design, fabricate, and water tunnel test a ¿ scale technology demonstrator to provide a hardware demonstration of BDSP thrust enhancement and develop the necessary BDSP designtechnology for prototype development. The proposed Phase II options will tailor the BDSP concept for the target torpedo platform with the design, fabrication and water tunnel testing of a prototype torpedo propulsor. A key element of this prototype testis demonstration of potential acoustic signature reduction of the BDSP concept. This prototype test will provide the engineering database for rapid Phase III transition of this technology to the Navy fleet. This BDSP concept can provide greatly increasedpropeller thrust for a given propeller diameter leading to both increased speed and/or maneuverability. This technology has direct application to torpedoes, unmanned underwater vehicles (UUVs), maneuvering thrusters, submarines, and other propeller drivendevices. Alternately, this technology offers reduced radiated noise while maintaining current thrust levels through both reduction in propulsor rotation speed and acoustic cancellation, which has direct application to torpedo and submarine acousticsignature reduction.In addition, this thrust enhancement technology has much broader applications in the development of high performance axial pumps, fans and compressors, offering the potential for much higher-pressure ratio devices with a reduction in moving parts. Thistechnology has the potential for reducing the size, increasing performance, reducing radiated noise, and reducing cost of a wide range of pump systems and air handling system.