Apparatus and method for reducing fluid drag on a submerged surface
AssigneeNorth Shore Partners
InventorsDonald Stubblefield, Jerry Stubblefield
Life of this patent
Estimating the term…
Abstract
An apparatus and method for reducing surface friction drag on the hull of a surface vessel by entraining air into water flowing in the boundary layer flow along the hull. A hemispherical protrusion creates flow separation by diverting a portion of the water flow away from the surface of the hull, which results in a reduced pressure region downstream from the protrusion. A vent located on the protrusion allow air to flow into the reduced pressure region. The air in the reduced pressure region is entrained into the water due to turbulent mixing from vortices shed on to the rear of the protrusion.
Claims22
An apparatus that entrains a secondary fluid into a primary fluid flow flowing along a surface of an object, the apparatus comprising:
- at least one member located on the surface of the object, the at least one member having a first portion that protrudes from the surface of the object and an opening located on the first portion, the opening being connected to a non-pressurized source of the secondary fluid;
- and
- whereby the first portion and the opening are configured to draw the secondary fluid through the opening as a first portion of the primary fluid flows over the at least one member at a velocity equal to or greater than a first critical velocity relative to the surface of the object.
An apparatus that entrains a secondary fluid into a primary fluid flow while the primary fluid flows along a surface of an object, the apparatus comprising:
- means for creating a pocket of the secondary fluid located between the surface of the object and the primary fluid;
- and
- means for turbulently mixing the primary fluid and the secondary fluid in the pocket, which results in entrainment of the secondary fluid into the primary fluid.
A method for reducing frictional drag on an object designed to be moved through or atop a primary fluid, the object having a surface that is at least partially submerged in the primary fluid, the method comprising:
- creating a reduced pressure region located between the first portion of the primary fluid and the surface of the object;
- providing an opening that enables a secondary fluid to flow into the reduced pressure region, the secondary fluid having a lower density than the primary fluid;
- and
- entraining at least a portion of the secondary fluid into a portion of the primary fluid by turbulently mixing the primary fluid and secondary fluid.
An apparatus that entrains a secondary fluid into a primary fluid flow flowing along a surface of an object, the apparatus comprising:
- at least one member located on the surface of the object, the at least one member having a first portion that protrudes from the surface of the object, the first portion being shaped to create flow separation between a first portion of the primary fluid and the surface of the object as the first portion of the primary fluid flows over the at least one member at a velocity equal to or greater than a critical velocity relative to the surface of the object, the flow separation of the first portion of the primary fluid defining a first region located between the surface of the object and the first portion of the primary fluid;
- and
- an opening located on the protruding portion of the at least one member that enables the secondary fluid to flow into the first region;
- and
- whereby the primary fluid and the secondary fluid are turbulently mixed in the first region or downstream from the first region, which results in entrainment of the secondary fluid into the primary fluid.
Dependencies are inferred from the claim text.