IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
US-0318879
(2009-01-12)
|
등록번호 |
US-8196536
(2012-06-12)
|
발명자
/ 주소 |
|
출원인 / 주소 |
|
대리인 / 주소 |
|
인용정보 |
피인용 횟수 :
2 인용 특허 :
10 |
초록
▼
An apparatus to reduce skin friction drag on a marine hull by imparting ultrasonically-induced cavitation at a boundary layer of a hull-water interface. The apparatus comprises a sonification plate mounted or adapted to be mounted on at least a portion of a wettable area of the hull (interior or ext
An apparatus to reduce skin friction drag on a marine hull by imparting ultrasonically-induced cavitation at a boundary layer of a hull-water interface. The apparatus comprises a sonification plate mounted or adapted to be mounted on at least a portion of a wettable area of the hull (interior or exterior) to define a boundary layer region with the water medium, a power source to energize the sonification plate, and a controller to regulate the frequency and/or intensity of microcavitation bubbles produced at the boundary layer 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 therein, which may be mounted on all or a portion of the hull. Energizing the transducers nucleates microcavitation bubbles upon entrained gases and/or particulate matter residing in the water medium.
대표청구항
▼
1. A surface-planing hull of a marine vessel that proceeds through a water medium with reduced frictional drag, said hull comprising: a reduced submerged region while planing,a sonification plate mounted near an aft region of said hull and forming at least part of said submerged region of said surfa
1. A surface-planing hull of a marine vessel that proceeds through a water medium with reduced frictional drag, said hull comprising: a reduced submerged region while planing,a sonification plate mounted near an aft region of said hull and forming at least part of said submerged region of said surface-planing hull to establish a boundary layer between said plate and the water medium when said hull is underway through said water medium, said sonification plate extending substantially over a wetted area near said aft region of said hull,a source of acoustic power to excite said sonification plate to generate acoustic waves in said boundary layer at a frequency and intensity to nucleate cavitation within said boundary layer, anda controller to enable activation of said source of acoustic power according to operational status of said vessel. 2. The hull of claim 1, wherein said source of power energizes said sonification plate to generate acoustic waves having a frequency range of 16 KHz to 200 KHz of a magnitude that exceeds tensile strength of the water medium in said boundary layer. 3. The hull of claim 2, wherein said controller regulates the intensity of said acoustic waves within a range of one to ten watts per square centimeter more or less in order to fracture a tensile strength of the water medium according to conditions of the water medium in said boundary layer, whereby to regulate size and duration of cavitation bubbles according to one or more of entrained air, particulate matter, impurities, debris, temperature, and other factors that impact degree of nucleation and tensile strength of said water medium. 4. The hull of claim 2, wherein said controller regulates intensity and duty cycle of said source of power in accordance with cavitation nuclei residing in said water medium. 5. The hull of claim 2, wherein said controller controls the frequency and/or intensity of said acoustic waves to regulate size, duration, and/or density of cavitation bubbles in said boundary layer in accordance with conditions of water medium. 6. The hull of claim 2, wherein said hull has a running pad on which the hull planes when underway and said sonification plate is positioned in a region of said running pad. 7. The hull of claim 6, further including a ventilation step forward of said running pad, and said step includes a sonification plate on a submerged portion thereof whereby to further reduce wetted area resistance of said vessel. 8. The hull of claim 2, wherein said vessel includes trim tabs that include auxiliary sonification plates thereon whereby to further reduce wetted area resistance of said vessel. 9. The hull of claim 1, wherein said sonification plate comprises an internal surface of said hull fitted with an insonifying device to impart acoustic energy into and through said hull into said water medium. 10. The hull of claim 1, wherein said sonification plate comprises a separate plate mounted on an exterior surface of said hull. 11. A deep-V planing marine hull comprising a deadrise at a transom thereof greater than 20 degrees and at least one sonification plate disposed near an aft region of said planing hull at a wettable area of said deadrise, said sonification plate being powered by an acoustic generator and extending substantially over said wetted area near said aft region of said hull whereby to nucleate cavitation bubbles at a boundary layer interface between said wettable area and a water medium while said vessel is on plane. 12. The deep-V hull of claim 11, wherein said acoustic generator includes a source of acoustic power to excite transducers of said sonification plate to generate acoustic waves having a frequency range of 16 KHz to 200 KHz of a magnitude that exceeds tensile strength of the water medium in said boundary layer. 13. The deep-V hull of claim 12, wherein said source of power includes a controller to regulate intensity of said acoustic waves within a range of one to ten watts per square centimeter more or less in order to fracture a tensile strength of the water medium according to conditions of the water medium in said boundary layer, whereby to regulate size and duration of cavitation bubbles. 14. The deep-V hull of claim 13, wherein said controller regulates frequency of said source of power in accordance with nuclei residing in said water medium. 15. The deep-V hull of claim 13, wherein said controller controls duty cycle and/or intensity of said acoustic waves to regulate size, duration, and/or density of cavitation bubbles in said boundary layer in accordance with conditions of water medium. 16. A hull of a marine surface vessel that proceeds through a water medium with reduced frictional drag, said hull comprising: a sonification plate forming at least part of a wettable surface of said hull, said sonification plate including a series of acoustic transducers to impart acoustic waves at a boundary layer interface between said water medium and said wettable surface,an acoustic generator to energize the transducers with an acoustic signal having an intensity sufficient to nucleate cavitation bubbles upon cavitation nuclei in said water medium, anda controller to control at least one of frequency, intensity, and duty cycle of said acoustic signal to grow cavitation bubbles to a desired number, size, or density within said boundary layer in accordance with surface conditions of the water medium and exposure time of said cavitation bubbles to acoustic waves produced by said transducers in relation to speed of said vessel whereby to effectively reduce frictional drag encountered by said vessel. 17. The hull of claim 16, wherein said sonification plate has a length and associated number of transducers in a fore-aft direction of said vessel to impart multiple acoustic cycles to the water medium in the boundary layer in order to grow said cavitation bubbles by rectified diffusion to said desired number, size, and density in relation to the speed of said vessel. 18. The hull of claim 17, wherein said acoustic generator imparts an acoustic energy to said water medium of one to ten watts per square centimeter, more or less. 19. The hull of claim 18, wherein said generator operates within a frequency range of 16-200 kHz.
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