Integrated Hull Design, Boundary-Layer Control, and Propulsion of Submerged Bodies

Abstract

Power requirements of large submerged bodies at high Reynolds numbers are optimized by the hydrodynamic synthesis of body design, boundary-layer control, and propulsion. Conventional rigid skin, all turbulent boundary layers, and a single suction slot are accepted as realistic engineering constraints. A 3:1 body has been designed and has been tested in a wind tunnel at a Reynolds number of 10; the wake drag has been found to be CDW = 0.002, and the equivalent suction drag CDS = 0.0142 yielding a total equivalent drag CD = 0.0162 (based on volume). This can be compared to CD = 0.0235 for the best conventional streamlined body (Akron airship model). A total engine power coefficient has also been determined, Cp* = 0.01585, while a conventional streamlined vehicle with stern wake propeller has a Cp* = 0.0215, thereby showing a net gain of 26%. There is a possible tradeoff between suction and propulsion powers allowing the total power coefficient to decrease to CP* = 0.0100 and to reach a 50% power gain.