IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
US-0929398
(2011-01-21)
|
등록번호 |
US-8677918
(2014-03-25)
|
발명자
/ 주소 |
|
출원인 / 주소 |
|
대리인 / 주소 |
|
인용정보 |
피인용 횟수 :
2 인용 특허 :
9 |
초록
▼
A marine vessel comprising a hull having a wetted area when underway on a surface of a body of water, a series of spaced transducer sections positioned in the wetted area of the hull, and an acoustic generator to energize the transducers to produce acoustic waves having an intensity sufficient to nu
A marine vessel comprising a hull having a wetted area when underway on a surface of a body of water, a series of spaced transducer sections positioned in the wetted area of the hull, and an acoustic generator to energize the transducers to produce acoustic waves having an intensity sufficient to nucleate cavitation upon cavitation nuclei suspended in the water medium. Suspended cavitation nuclei include entrained gases, particulate matter, microbubbles formed from wind-blown breaking waves, and/or phase-boundaries at gas-water or solid-water interfaces in the water medium. The intensity, duty cycle and/or frequency of the acoustic waves are determined and/or regulated according to water conditions to produce microcavitation bubbles in the boundary layer between fifty and two hundred microns in size or to optimally reduce drag. An operator or controller may dynamically regulate the frequency, intensity, and/or duty cycle of acoustic waves according to vessel speed and/or sea surface conditions.
대표청구항
▼
1. A marine vessel that travels on a surface of a body of water, said vessel comprising: a hull having a wetted area when underway,a series of insonification sections positioned in said wetted area of said hull and contained within a sonification plate that is affixed against said hull,an acoustic g
1. A marine vessel that travels on a surface of a body of water, said vessel comprising: a hull having a wetted area when underway,a series of insonification sections positioned in said wetted area of said hull and contained within a sonification plate that is affixed against said hull,an acoustic generator to power said insonification sections to produce acoustic waves having an intensity sufficient to nucleate cavitation upon cavitation nuclei suspended in said water, anda wiring harness to distribute power from the acoustic generator to said series of insonification sections. 2. The marine vessel of claim 1, wherein said sonification plate is filled with foam or other a water blocking material to prevent wetting of insonifying devices or circuitry thereof. 3. The marine vessel of claim 1, wherein said insonification sections have a spacing in a fore-aft direction, and said spacing is determined according to vessel operating speed, nature of said acoustic waves, and/or conditions of the water in terms of cavitation nuclei and threshold or other condition. 4. The marine vessel of claim 1, wherein said acoustic generator produces a series of tone bursts of high-frequency acoustic energy to establish a pattern of cavitation that optimally reduces drag. 5. The marine vessel of claim 1, wherein said acoustic generator produces a tone burst of high-frequency acoustic energy having an initial high-frequency to initiate cavitation followed by a series of higher-frequency pulses to grow cavitation bubbles. 6. The marine vessel of claim 1, wherein said acoustic generator includes a common power supply to energize transducer pairs substantially equidistant from and positioned on opposite sides of a keel line of said hull in order to maintain symmetric drag reduction in the event of a failure of one of said transducers of said transducer pair. 7. The marine vessel of claim 1, wherein said acoustic generator is responsive to a wetted area sensor to activate a given one of said series of insonification sections. 8. The marine vessel of claim 1, wherein said hull is stepped, and said series of insonification sections are additionally provided in a wetted area fore of said step. 9. A marine vessel that travels on a surface of a body of water, said vessel comprising: a fiberglass hull having a wetted area when underway,a series of insonification sections embedded in said fiberglass and positioned in said wetted area of said hull,an acoustic generator to power said insonification sections to produce acoustic waves having an intensity sufficient to nucleate cavitation upon cavitation nuclei suspended in said water, anda wiring harness to distribute power from the acoustic generator to said series of insonification sections. 10. The marine vessel of claim 1, further including a controller to regulate at least one of intensity and duty cycle of said acoustic generator according to surface conditions of said water. 11. The marine vessel of claim 1, further including a controller to regulate at least one of intensity, frequency, and duty cycle of said acoustic generator according to speed of said vessel. 12. The marine vessel of claim 1, further including a controller to enable an operator to control at least one of intensity, frequency, and duty cycle of said acoustic generator. 13. The marine vessel of claim 1, further including a controller to intermittently or alternately supply power to respective insonification sections whereby to enable greater portion of available acoustic power to be instantaneously supplied to a given insonification section. 14. The marine vessel of claim 1, further including a wetness sensor to activate a given insonification section in response to a wetted condition thereof whereby to conserve power when portions of said hull become aerated during high-speed planing. 15. The marine vessel of claim 1, wherein said hull comprising a planing hull having a reduced wetted area while on plane, and said series of acoustic transducers are positioned against said hull in said reduced wetted area. 16. The marine vessel of claim 1, wherein the acoustic generator produces an ultrasonic tone burst signal that imparts to said water an acoustic wave having a momentary intensity between 0.5 and 1000 watts per square centimeter. 17. A method of reducing skin friction drag of a marine hull while underway in surface contact with a water body, said method comprising: providing insonifying transducers at a wetted region of said hull,energizing said transducers to produce acoustic waves having an intensity above a predetermined cavitation threshold that at least exceeds a tensile strength of said water medium to nucleate cavitation on cavitation nuclei suspended in said medium whereby to populate microcavities therein, andduring movement of said medium pass said insonifying transducers, exposing populated microcavities to tone bursts of acoustic waves having an intensity and frequency between eighteen and two hundred kilohertz in accordance with conditions of said water medium in order to grow said populated microcavities to a desired number, density, and/or size to achieve a desired drag reduction. 18. The method of claim 17, wherein a target size of said microcavities produced in said exposing step ranges between fifty and two hundred microns. 19. The method of claim 17, wherein said exposing step includes regulating a duty cycle of said tone bursts to provide a pattern of cavitation that achieves said desired drag reduction. 20. The method of claim 19, further including regulating the intensity and/or said duty cycle according to speed of said hull in relation to said water medium. 21. The method of claim 20, further including regulating both said intensity and duty cycle wherein the acoustic intensity ranges between 0.5 to 1000 watts per square centimeter and said duty cycle inversely ranges between 100% and 0.1%. 22. The method of claim 17, further including providing a distributor/controller to distribute tone bursts of acoustic signals among multiple insonifying transducers affixed about said hull in order to produce microcavitation bubbles about a wetted area of said hull. 23. The method of claim 22, further including alternately or periodically distributing tone bursts of acoustic signal among said insonifying transducers. 24. The method of claim 19, further comprising dynamically determining said cavitation threshold while said hull is underway and adjusting the intensity according to said dynamically determined threshold. 25. The method of claim 17, wherein said providing step includes providing said transducers inside a water-tight sonification plate having a diaphragm side and a abutment side, and mounting the abutment side of said sonification plate against a wetted region of said hull. 26. A marine vessel that travels on a surface of a body of water, said vessel comprising: a hull having a wetted area when underway on said surface of said body of water,a series of spaced transducer sections positioned about said wetted area, andan acoustic generator to energize said transducers to produce acoustic waves having an intensity determined according to conditions of said water that is sufficient to nucleate cavitation upon cavitation nuclei suspended in said water wherein the acoustic generator produces an ultrasonic tone burst signal that imparts to said water an acoustic wave having a momentary intensity between 0.5 and 1000 watts per square centimeter. 27. The vessel of claim 26, wherein the intensity and a frequency of said acoustic generator is determined to produce acoustic waves to achieve a target size of microcavitation bubbles that includes a size between fifty and two hundred microns. 28. The vessel of claim 26, wherein spacing between said transducer sections in a fore-aft direction is determined according to at least one of vessel operating speed, nature of said acoustic waves, and conditions of the water. 29. The vessel of claim 26, further including a controller to regulate intensity and/or duty cycle of said acoustic waves according to vessel speed.
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