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, a voice coil actuator, 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 via the voice coil actuator 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
19 Claims
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1. A method comprising:
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providing a watercraft, the watercraft comprising a hull, a fluid chamber, a voice coil actuator, 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 via the voice coil actuator in a manner such that fluid is expelled from the fluid port into the liquid stream boundary layer. - View Dependent Claims (2, 3, 4)
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5. A method comprising:
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providing a watercraft, the watercraft comprising a hull, a fluid chamber, first and second fluid ports, and first and second valves, the first fluid port allowing fluid communication between the fluid chamber and a liquid environment external to the watercraft, the second fluid port allowing communication of fluid between the fluid chamber and the gaseous environment external to the watercraft, each of the first and second valves being movable between opened and closed positions, the first valve being configured and adapted to prevent fluid communication between the first fluid port and the fluid chamber when in its closed position and to allow such communication when in its opened position, the second valve being configured and adapted to prevent fluid communication between the second fluid port and the fluid chamber when in its closed position and to allow such communication when in its opened position;
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 the decreasing of the internal volume of the fluid chamber causes the expulsion of fluid in a gaseous state from the first fluid port into the liquid stream boundary layer and such that the increasing of the internal volume of the fluid chamber causes fluid in a gaseous state to be drawn into the fluid chamber from a gaseous environment external to the watercraft, the decreasing of the internal volume of the fluid chamber occurring with the first valve in its opened position and the second valve in its closed position and the increasing of the internal volume of the fluid chamber occurring with the first valve in its closed position and the second valve in its opened position.
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6. 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 and in a manner such that fluid expelled from the fluid port into the liquid stream boundary layer is in a liquid state as it is expelled. - View Dependent Claims (7, 8, 9, 10)
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11. A method comprising:
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providing a watercraft, the watercraft comprising a hull, a voice coil actuator, 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 via the voice coil actuator. - View Dependent Claims (12, 13, 14, 15, 16)
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17. 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;
a voice coil actuator operatively connected to the reciprocating member in a manner such that the voice coil actuator is capable of moving the reciprocating member from the first position to the second position; and
an opening through the exterior surface of the hull, the opening forming a portion of the fluid passageway. - View Dependent Claims (19)
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18. A watercraft surrounded by an external environment, the 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, the opening providing the sole fluid connection between the fluid passageway and the external environment.
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Specification