Accession Number : ADD018239

Title :   Dualcavitating Hydrofoil Structures.

Descriptive Note : Patent, Filed 31 Mar 95, patented 3 Sep 96,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Shen, Young T

Report Date : 03 Sep 1996

Pagination or Media Count : 15

Abstract : The invention is directed to hydrofoil structures for efficient operation over a wide speed range from subcavitating to supercavitating operation. A dualcavitating hydrofoil is provided that overcomes cavitation problems associated with high speed operation of prior art subcavitating hydrofoil structures by providing a supercavitating profile shape in the lower surface to achieve a supercavitating condition at high speeds and that overcomes problems associated with low speed operation of prior art supercavitating hydrofoil structures by providing an upper surface that combines with the lower surface to form a streamlined cross-sectional shape that achieves a smooth flow exit at the trailing edge for efficient, low drag, high lift subcavitating operation. The lower surface is shaped to efficiently produce a lift force during normal supercavilating operation wherein the lower surface functions to generate a cavity extending aft from the leading edge, the upper surface being completely enveloped within the cavity and the lower surface being at least partially wetted during normal supercavitating operation. The upper surface is shaped to efficiently produce a lift force during normal subcavitating operation wherein the upper and lower surfaces are fully wetted during normal subcavitating operation.

Descriptors :   *PATENTS, *CAVITATION, *HYDROFOILS, HYDRODYNAMIC CHARACTERISTICS, HIGH VELOCITY, STRUCTURAL ANALYSIS, BOUNDARY LAYER, ANGLE OF ATTACK, LOW VELOCITY, LEADING EDGES, HIGH LIFT, FLOW SEPARATION, LOW DRAG, TRAILING EDGES, STREAMLINE SHAPE

Subject Categories : Fluid Mechanics
      Marine Engineering

Distribution Statement : APPROVED FOR PUBLIC RELEASE