Method and device for low-noise underwater propulsion and for reducing hull drag
First Claim
1. A method comprising:
- providing a watercraft, the watercraft comprising a hull, a fluid chamber, and at least one fluid port, the fluid port allowing fluid communication between the fluid chamber and a liquid environment external to the watercraft;
propelling the watercraft within the liquid environment in a manner such that a liquid stream boundary layer exist adjacent the hull of the watercraft; and
repetitively increasing and decreasing the internal volume of the fluid chamber in a manner such that fluid is expelled from the fluid port into the liquid stream boundary layer.
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Accused Products
Abstract
A method and apparatus is disclosed for producing propulsion underwater with minimal acoustical emission. In basic concept, the method comprises the expulsion and sucking of liquid into and out of a liquid port of a watercraft in a manner generating compression and expansion waves adjacent the liquid port. Such expansion and compression waves generate a positive net thrust on the watercraft in a direction opposite that of their expulsion. Also disclosed is a method and apparatus for reducing the drag caused by hull skin friction by actively increasing the momentum of the liquid stream boundary layer adjacent a watercraft via the expulsion of fluid (liquid or gas) from ports in the hull of such a watercraft.
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Citations
20 Claims
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1. A method comprising:
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providing a watercraft, the watercraft comprising a hull, a fluid chamber, and at least one fluid port, the fluid port allowing fluid communication between the fluid chamber and a liquid environment external to the watercraft;
propelling the watercraft within the liquid environment in a manner such that a liquid stream boundary layer exist adjacent the hull of the watercraft; and
repetitively increasing and decreasing the internal volume of the fluid chamber in a manner such that fluid is expelled from the fluid port into the liquid stream boundary layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method comprising:
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providing a watercraft, the watercraft comprising a hull and a reciprocating member;
providing a liquid environment external to the watercraft, the liquid environment being in liquid communication with the reciprocating member of the watercraft;
propelling the watercraft within the liquid environment in a manner such that a liquid stream boundary layer exist adjacent the hull of the watercraft; and
increasing momentum within the liquid stream boundary layer by moving the reciprocating member in a linearly reciprocating manner relative to the hull of the watercraft. - View Dependent Claims (11, 12, 13, 14, 15)
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16. A watercraft comprising:
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a hull, the hull having an exterior surface;
a reciprocating member, the reciprocating member being operatively connected to the hull in a manner such that the reciprocating member is linearly movable between first and second positions in a reciprocating manner;
a fluid passageway that is partially bound by the reciprocating member; and
an opening through the exterior surface of the hull, the opening forming a portion of the fluid passageway. - View Dependent Claims (17, 18, 19, 20)
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Specification