SOLUTIONS   Hydrodynamic and Naval Systems

OVERVIEW

CDI has been active in the study of key issues in submarine hydrodynamics for over 25 years. During the 1980s and 1990s, CDI supported a number of studies by the Johns Hopkins University Applied Physics Lab as well as NAVSEA- and CNO- sponsored the activities on SSN/SSBN Security and Survivability. This work entailed significant contributions to the modeling of the complex vortex wake systems of submarines, including both near-field studies of vortex wake development and long-time analyses of pancake eddies. These phenomena play a significant role in critical issues of acoustic and nonacoustic antisubmarine warfare.


Schematic of key hydrodynamic mechanisms in the wake of a typical submarine


As described in subsequent web pages, CDI also led a combined experimental and modeling activity during 1995-1999 developing and demonstrating a vortex wake mitigation system for submarines, built around the use of novel "vortex leveraging" mechanisms as well as smart materials-based actuation devices. A series of water tunnel and tow tank experiments led to the validation of this approach, many of whose key elements are also directly applicable to aircraft wake dissipation and are embodied in U.S. Patent 6,042,059. This work on smart materials technology for marine applications led to design of novel system to replace conventional rudder/propeller steering systems for both surface combatants and submarines. This ONR-sponsored activity led to the design and testing of a novel "smart duct" system, a variable geometry ducted propulsor suitable for a wide range of marine systems including Unmanned Undersea Vehicles (UUVs).


Notional DDX surface combatant (left) and modeling of conventional rudder/ propeller steering system


Finally, CDI's work has included not only computational modeling prototype device development, but also on-site testing in the company water tunnel, as well as off-site experimental campaigns at facilities such as the NSWC Carderock 36" water tunnel.


CDI 2' x 2' water tunnel (left) and NSWC Carderock 36" Large Cavitation Channel (LCC) - sites of past testing activities.

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