Drag and Noise Measurements on Underwater Vehicles with a Riblet Surface Coating

摘要

The purpose of this study was to investigate both the drag and noise reducing effects of riblet surface coatings on a marine vehicles. The use of microgrooves, or riblets, for skin friction reduction originated at NASA Langley for aerodynamic applications. Water tunnel tests at the Naval Ocean Systems Center (NOSC), San Diego, have shown that reductions in skin friction of up to 8% can be achieved with sharp peaked riblets of appropriate size, when applied to a flat plate in a turbulent boundary layer. It is reasonable to suspect that a reduction in flow noise might accompany the measured reduction in skin friction. In fact, wind tunnel tests on a flat plate, conducted in cooperation with University of California at fullerton, indicate a 2-3 dB reduction in noise at the peak in the turbulent boundary layer spectrum when riblets are used. The flat plate laboratory experiments led to the current effort to study hydrodynamic drag and noise reduction on underwater vehicles. Because undersea vehicles are subject to fouling from marine organisms, the effect of biofouling on riblets was also studied. Skin drag, Boundary layer, Buoyant vehicles, Riblets. (jes)