Accession Number : ADD018389

Title :   Dual Cavitating Hydrofoil Structures for Multi-Speed Applications.

Descriptive Note : Patent, Filed 25 Jun 96, patented 11 Feb 97,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Shen, Young T

Report Date : 11 Feb 1997

Pagination or Media Count : 16

Abstract : A hydrofoil structures for efficient operation over a wide speed range from subcavitating to supercavitating operation is provided. The dualcavitating hydrofoil overcomes cavitation problems associated with high speed operation of prior art subcavitating hydrofoils by providing a supercavitating profile shape in the lower surface to achieve a supercavitating condition at high speeds and overcomes performance related problems associated with low speed operation and structural problems associated with high speed operation of prior art supercavitating hydrofoils by providing a profile shape having a robust trailing edge that employs the Coanda effect to achieve a smooth flow exit at the trailing edge. The dualcavitating hydrofoil includes upper and lower surfaces defining a profile that includes a tapered section adjacent to and extending aft from the leading edge and a thick curved section adjacent to and extending forward of the trailing edge. The dualcavitating hydrofoil also includes boundary layer circulation control means for generating a flow over the trailing edge region such that boundary layer separation over the upper surface is avoided during normal subcavitating operation.

Descriptors :   *PATENTS, *CAVITATION, *HYDROFOILS, LEADING EDGES, HIGH LIFT, FLOW SEPARATION, BOUNDARY LAYER CONTROL, MARINE PROPULSION, TRAILING EDGES, DRAG REDUCTION, HYDRODYNAMIC CONTROL SURFACES, COANDA EFFECT, STRUCTURAL INTEGRITY

Subject Categories : Marine Engineering
      Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE