Accession Number : AD0784122

Title :   Drag Reduction of a Hull by Electrolysis.

Descriptive Note : Research rept.,

Corporate Author : NAVAL ACADEMY ANNAPOLIS MD

Personal Author(s) : Thornton,Wayne A.

Report Date : 21 MAY 1974

Pagination or Media Count : 90

Abstract : An experiment was conducted to study the drag reduction on a hull resulting from injection of gas bubbles into the boundary layer by electrolysis. The resulting drag reduction on an eighteen foot model was found to depend on the towing velocity and the time-rate of gas bubbles produced at the electrodes. The drag reduction obtained at a fixed current of 4 amperes was found to vary between 3.2% at the lower towing speeds and 17.5% in the middle of the speed range. With increasing speed, the bubble injection had a diminishing effect. For the maximum drag reduction, the power requirement was 50.4 watts. Projecting these results to prototype application, it appears that the effect is a function of the wetted surface area of the hull. (Author)

Descriptors :   *Drag reduction, *Hulls(Marine), *Bubbles, *Electrolysis, Injection, Boundary layer control, Model tests, Hydrodynamics, Test facilities, Towing, Velocity, Time dependence, Mass flow, Electrodes

Subject Categories : Marine Engineering
      Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE