IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
US-0483301
(2012-06-11)
|
등록번호 |
US-8539895
(2013-09-24)
|
발명자
/ 주소 |
|
출원인 / 주소 |
|
대리인 / 주소 |
|
인용정보 |
피인용 횟수 :
1 인용 특허 :
9 |
초록
▼
An apparatus of reducing skin friction drag on a marine hull comprising imparting ultrasonically-induced cavitation at a boundary layer at the hull-water interface. The apparatus includes a sonification plate on at least a portion of a wettable area of the hull to establish a boundary layer interfac
An apparatus of reducing skin friction drag on a marine hull comprising imparting ultrasonically-induced cavitation at a boundary layer at the hull-water interface. The apparatus includes a sonification plate on at least a portion of a wettable area of the hull to establish a boundary layer interface between the sonification plate and the water medium, and an acoustic generator for energizing the sonification plate to produce microcavitation bubbles at the boundary layer interface whereby to alter the Reynolds number, kinematic viscosity, and coefficient of friction. The sonification plate is hermetically sealed and includes an array of ultrasonic transducers, which may be mounted on an interior or exterior surface of the hull. The energizing nucleates microcavitation bubbles upon entrained gases and/or particulate matter residing in the water medium.
대표청구항
▼
1. In combination with a marine vessel having a planing hull and a wetted area at an interface between an aft region of the hull and a water fluid medium when underway and on plane over said medium, an apparatus comprising a source of power, an acoustic signal generator powered by said source of pow
1. In combination with a marine vessel having a planing hull and a wetted area at an interface between an aft region of the hull and a water fluid medium when underway and on plane over said medium, an apparatus comprising a source of power, an acoustic signal generator powered by said source of power, a sonification plate adapted for mounting on at least on at least a portion of said wetted area, and a transducer assembly excited by said generator to acoustically generate cavitation bubbles in a boundary layer of the interface near the aft region of said planing hull wherein components of said transducer assembly are hermetically sealed from water exposure when positioned in said sonification plate, whereby to reduce skin friction drag at said interface. 2. The apparatus of claim 1 further comprising: a controller to control at least one of duty cycle and intensity of said energizing according to a condition of the water medium that include at least one of amount of entrained gases, particulate matter, impurities, debris, and other factors that impact the degree of cavity nucleation and/or the tensile strength of the water medium through which the vessel proceeds. 3. The apparatus of claim 2 wherein said sonification plate comprises an array of transducers disposed within said sonification plate, said sonification plate being hermetically sealed, and said sonification plate being adapted for mounting on at least a portion of the wetted area of said hull. 4. The apparatus of claim 2, wherein said array of ultrasonic transducers nucleates microcavitation bubbles upon entrained gases and/or particulate matter residing in said water fluid medium. 5. The apparatus of claim 2, wherein said transducers are energized by said generator to generate cavitation bubbles in the water fluid medium to alter a Reynolds Number Re=(ρνL)/μ=νL/η at said boundary layer interface of the wetted area of the hull, where L is length of travel of water fluid medium along the hull, ρ is density of water fluid medium, ν is velocity of the marine vessel relative to the water fluid medium, μ is viscosity of the water fluid medium, and η is kinematic viscosity of the water fluid medium. 6. The apparatus of claim 5, wherein said transducers produce a series of acoustic waves having a frequency range between ten thousand and one hundred thousand kilohertz. 7. The apparatus of claim 1, wherein an intensity or duty cycle of said generator is controlled in accordance with a condition of the water medium at said interface to maintain optimum or efficient drag reduction. 8. The apparatus of claim 6, wherein said generator is energized to produce acoustic waves having an intensity level to at least break a surface tension of the water fluid medium at said interface. 9. An apparatus to reduce frictional drag on a planing hull of a marine vessel when underway comprising: a sonification plate having a mounting surface for positioning on at least a portion of a wetted area of an aft region of said hull and an acoustic surface for emitting acoustic waves in response to a series of transducers positioned inside said sonification plate opposite said acoustic surface,an acoustic signal generator to energize said transducers with a signal to activate said acoustic surface to acoustically generate cavitation bubbles by emitting acoustic waves having an intensity that exceeds tensile strength of water in and about a boundary layer at an interface between the aft region of the hull and said water whereby to reduce wetted area resistance of said hull while underway, andwherein components inside said sonification plate are sealed from water exposure when mounted on a submersible portion of the hull of said vessel. 10. The apparatus of claim 9, wherein said sonification plate produces acoustic waves within a range of ten thousand to one hundred thousand kilohertz. 11. The apparatus of claim 10, wherein said sonification plate produces acoustic waves having an intensity that at least breaks a surface tension of water exposed to said hull. 12. The apparatus of claim 11, wherein said generator includes a power level controller to regulate the intensity of said acoustic waves in a general range of one to ten watts per square centimeter more or less that is sufficient to break a tensile strength of the water according to conditions of the water interfacing said hull, whereby to regulate size and duration of cavitation bubbles and to reduce unnecessary energy consumption in water having excessive nuclei upon which to nucleate cavitation and/or to allow dissipation of cavitation bubbles in time to prevent undue cavitation interference with a propulsion mechanism of said vessel located aft of said sonification plate. 13. The apparatus of claim 11, wherein said generator provides a duty cycle or intensity control of said energizing whereby to establish size, duration, and/or density of cavitation bubbles for optimum or efficient drag reduction in accordance with conditions of water interfacing said hull wherein the conditions include at least one of amount of entrained gases, particulate matter, impurities, debris, temperature, salinity, and other factors that impact the degree of cavity nucleation and/or the tensile strength of the water through which the vessel proceeds. 14. The apparatus of claim 11, wherein said sonification plate extends over an entire wetted area of said hull. 15. The apparatus of claim 11, wherein said sonification plate is disposed on a running pad of said planing hull. 16. The apparatus of claim 11, further including a secondary sonification plates that extends on trim tabs of said vessel whereby to further reduce wetted area resistance of said trim tabs. 17. The apparatus of claim 11, wherein said hull includes ventilation steps and said sonification plate is disposed on a submerged portion of at least one ventilation step whereby to further reduce wetted area resistance of said vessel. 18. An apparatus to improve efficiency of operation of a planing hull marine vessel by reducing wetted area resistance of a hull thereof while underway, said apparatus comprising: an insonification region on a submerged portion of an aft region of said planing hull at which to acoustically generate microcavitation bubbles, andan acoustic signal generator to energize said insonification region to acoustically generate microcavitation bubbles within a boundary layer of said submerged region between the hull of said vessel and a medium of water whereby to reduce wetted area resistance of said vessel while underway wherein intensity of acoustic waves imparted to said medium lies in a general range of one to ten watts per square centimeter more or less that is sufficient to break tensile strength of water according to a condition of the medium of water interfacing said hull, whereby to established a desired size and duration of cavitation bubbles and to reduce unnecessary energy consumption in water having excessive nuclei upon which to nucleate cavitation and/or to allow dissipation of cavitation bubbles in time to prevent cavitation damage to components of said vessel. 19. The apparatus of claim 18, wherein said insonification region produces ultrasonic waves at said boundary layer having a frequency range between ten thousand and one hundred thousand kilohertz at a power level to at least break surface tension of said medium of water. 20. The apparatus of claim 19, wherein said insonification region includes a series of ultrasonic transducers to generate said microcavitation bubbles and said generation includes a controller to control one of duty cycle and power level of exciting said transducers for optimum or efficient drag reduction according to at least one condition of said medium of water that includes at least one of amount of entrained gases, particulate matter, impurities, debris, temperature, salinity, and other factors that impact degree of cavity nucleation and/or tensile strength of the medium of water through which the vessel proceeds.
※ AI-Helper는 부적절한 답변을 할 수 있습니다.