High-Speed (Supercavitating) Undersea Weapon
The objective of the High-Speed Undersea Weaponry project is to develop vehicle guidance, control, and maneuvering capabilities for quick reaction/delivery weapons. This effort could lead to the design of autonomous high-speed undersea weapons, a revolution in undersea warfare. High-speed weapons are expected to offer the Navy great tactical advantage for Anti-Submarine Warfare (ASW) and Anti-Surface Warfare (ASuW) close encounter scenarios. The new operational paradigm with emphasis on the littoral will require rapid weapon systems response at ranges close to the naval platform. The overall system response of a high-speed weapon for breaking off engagements with undersea threats would be measured in seconds vice minutes.
The Office of Naval Research High-Speed Undersea Weapons project has three tasks: (1) Supercavitation Physics, (2) Vehicle Guidance, and (3) Vehicle Control. Supercavitation Physics deals with the fundamental understanding of supercavitation, and numerical calculation of two-phase flows. Vehicle Guidance deals with acoustic and non-acoustic sensors, signal processing, waveform design, homing techniques and the auto pilot and controller that are used to guide (either autonomously or with external interaction) the weapon to its target.
Technical issues include quantification of flow noise, optimization of wetted areas for sensors and controls, and ultra high-speed signal processing. Vehicle Control deals with the control and maneuvering of the high-speed weapon, with emphasis on stabilizing the supercavitating bubble cavity and optimizing the bubble shape for reduced drag. Technical issues include unsteady bubble cavity behavior, instability due to vehicle planing and tail slap, and interaction between the cavity and propulsion exhaust. Accordingly, adaptive cavitator, ventilation requirement, control surfaces and control algorithms have to be developed. Analyses, numerical calculations, modeling and simulations, test and evaluations are required to support these three tasks. Lastly, integration of vehicle homing and control systems and sub-systems with tactics is needed to develop a Test Bed for in-water demonstrations.
The ONR propulsion program for high-speed supercavitating weapons focuses primarily on power sources based on the water-combustion of hydroreactive metallic fuels, particularly aluminum-based fuels. Therefore, proposals are sought that fall under on one or more of the following topics: (1) engineering development of hydroreactive power sources; (2) understanding the water-combustion of hydroreactive metals, alloys, and composites; (3) developing new hydroreactive metals, alloys and composites (particularly nanoscale materials) with enhanced water-combustion properties; and (4) controlling the initiation, sustainment, and power output of hydroreactive processes.
Besides providing direct engine thrust for a high-speed supercavitating weapon, hydroreactive metallic fuels can also be combusted with water to provide thermal energy, which can then be converted to electrical energy by various energy conversion technologies, such as turbines, thermoelectrics, and Stirling engines. Conversion of hydroreactive fuels to electrical energy may benefit the performance of the supercavitating vehicle (e.g., provide electrical power for guidance and control), as well as, serve as a novel high energy density power source for other undersea vehicles. Therefore, innovative concepts for generating electrical energy from hydroreactive fuels will also be considered for funding.