Patents Assigned to Cortana Corporation
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Patent number: 8039055Abstract: A method for increasing the efficiency of additive drag reduction by establishing a drag-reducing viscoelastic coating on a surface. The method includes mixing a polymer into a concentrated solution that has approximately the same density as a fluid flowing over the surface, ejecting the mixture/solution into the flowing fluid in a manner such that a coating of polymer, which initially grows thicker with time, is adsorbed onto the surface, and reducing the ejection rate of the first fluid such that the coating of polymer then grows thinner with time. These steps may be repeated so that a desired minimum coating thickness is maintained over an extended period of time. The method reduces the polymer expenditure rate for a given drag reduction. Moreover, the produced viscoelastic coating impedes the attachment and growth of drag-producing natural organisms and may be applied without “down-time” (e.g., while underway).Type: GrantFiled: January 2, 2008Date of Patent: October 18, 2011Assignee: Cortana CorporationInventors: Kenneth J. Moore, Thomas D. Ryan, Christopher M. Moore, Timothy A. Boyce
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Patent number: 6516652Abstract: A method is provided to select appropriate material properties for turbulent friction drag reduction, given a specific body configuration and freestream velocity. The method is based on a mathematical description of the balance of energy at the interface between the viscoelastic surface and the moving fluid, and permits determination of the interaction of turbulent boundary layer fluctuations with a viscoelastic layer by solving two subtasks—i.e., a hydrodynamic problem and an elasticity problem, which are coupled by absorption and compliancy coefficients. Displacement, velocity, and energy transfer boundary conditions on a viscoelastic surface are determined, and a Reynolds stress type turbulence model is modified to account for redistribution of turbulent energy in the near-wall of the boundary layer. The invention permits drag reduction by a coating with specified density, thickness, and complex shear modulus to be predicted for a given body geometry and freestream velocity.Type: GrantFiled: April 10, 2000Date of Patent: February 11, 2003Assignee: Cortana CorporationInventors: Carol L. May, Gennadiy A. Voropayev
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Patent number: 6435214Abstract: A method and apparatus for ejecting a second fluid into the near-wall region of the boundary layer of a first fluid, so that the second fluid hugs the wall. This alone reduces drag by modifying the behavior of the near-wall structure, thereby reducing the frequency of burst and sweep cycles, even when the first and second fluids are identical. Further, one or more additives, such as polymer, surfactant, micro-bubbles, a combination thereof, and/or using a second fluid having an elevated temperature as compared to the temperature of the first fluid, may be used to achieve much greater drag reduction as well as lower dissipation rates than previously possible. The second fluid is ejected using a convex Coanda surface (7) and at a controlled velocity that is a small fraction of the velocity of the first fluid moving along the wall so that the flow lines of the second fluid are substantially aligned with the flow lines of the first fluid.Type: GrantFiled: May 29, 2001Date of Patent: August 20, 2002Assignee: Cortana CorporationInventor: Victor V. Babenko
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Patent number: 6357374Abstract: In an apparatus and method for ejecting an additive for significantly reducing the drag of a first fluid moving relative to a wall, a drag-reducing substance is conditioned by causing a second fluid, which includes the drag-reducing substance as a dispersed solid, liquid or gas, to flow through a nozzle. The second fluid is then passed by a vortex chamber prior to ejection of the second fluid into the first fluid via an aperture that includes a Coanda surface on a portion thereof. Additional techniques are also disclosed which increase the effectiveness and efficiency of ejecting a drag-reducing substance into a fluid that is moving relative to a wall, and which thus enable multiple layers to be established without the undesirable disruption of the boundary layer and without the rapid diffusion of the additives across the boundary layer that occur in prior art ejection techniques.Type: GrantFiled: July 21, 2000Date of Patent: March 19, 2002Assignee: Cortana CorporationInventors: Kenneth J. Moore, Thomas D. Ryan, Vladimir A. Gorban, Victor V. Babenko
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Patent number: 6357464Abstract: A method for ejecting a second fluid into the near-wall region of the boundary layer of a first fluid, so that the second fluid hugs the wall. This alone reduces drag by modifying the behavior of the near-wall structure, thereby reducing the frequency of burst and sweep cycles, even when the first and second fluids are identical. Further, one or more additives, such as polymer, surfactant, micro-bubbles, a combination thereof, and/or using a second fluid having an elevated temperature as compared to the temperature of the first fluid, may be used to achieve much greater drag reduction as well as lower additive diffusion rates than previously possible. The second fluid is ejected using a convex Coanda surface (7) and at a controlled velocity that is a small fraction of the velocity of the first fluid moving along the wall.Type: GrantFiled: August 10, 2001Date of Patent: March 19, 2002Assignee: Cortana CorporationInventor: Victor V. Babenko
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Patent number: 6349734Abstract: Skin friction reduction on a surface moving relative to a fluid can be obtained by ejecting a polymer—water mixture/solution into the boundary layer. The efficacy of the ejected polymer—water mixture/solution is closely related to polymer dissipation out of the boundary layer and conditioning (i..e, lengthening, unwinding or stretching) of the polymer molecules by liquid shear forces immediately before ejection. The invention is a method for conditioning and ejecting a polymer—water mixture/solution that improves drag reduction characteristics of the mixture/solution and maintains the mixture/solution in the boundary layer for as long as possible. By improving the drag-reduction characteristics of the drag reducing substance mixture/solution and by extending the time it remains in the near-wall region, the ejector can increase the performance and reduce the volume and storage requirements of a drag-reduction system.Type: GrantFiled: October 30, 2000Date of Patent: February 26, 2002Assignee: Cortana CorporationInventor: Victor V. Babenko
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Patent number: 6305399Abstract: Skin friction reduction on a surface moving relative to a fluid can be obtained by ejecting a polymer—water mixture/solution into the boundary layer. The efficacy of the ejected polymer—water mixture/solution is closely related to polymer dissipation out of the boundary layer and conditioning (i.e, lengthening, unwinding or stretching) of the polymer molecules by liquid shear forces immediately before ejection. The invention is a method and apparatus for conditioning and ejecting a polymer—water mixture/solution that improves drag reduction characteristics of the mixture/solution and maintains the mixture/solution in the boundary layer for as long as possible.Type: GrantFiled: August 11, 2000Date of Patent: October 23, 2001Assignee: Cortana CorporationInventor: Victor V. Babenko
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Patent number: 6237636Abstract: Skin friction reduction on a surface moving relative to a fluid can be obtained by ejecting a polymer-water mixture/solution into the boundary layer. The efficacy of the ejected polymer-water mixture/solution is closely related to polymer dissipation out of the boundary layer and conditioning (i.e, lenthening, unwinding or stretching) of the polymer molecules by liquid shear forces immediately before ejection. The invention is a method and apparatus for conditioning and ejecting a polymer-water mixture/solution that improves drag reduction characteristics of the mixture/solution and maintains the mixture/solution in the boundary layer for as long as possible. By improving the drag-reduction characteristic in the polymer-water mixture/solution and by extending the time it remains in the near-wall region, the ejector can increase the performance and reduce the volume and storage requirements of a drag-reduction system.Type: GrantFiled: April 3, 2000Date of Patent: May 29, 2001Assignee: Cortana CorporationInventor: Victor V. Babenko
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Patent number: 6200014Abstract: Skin friction reduction on a surface moving relative to a fluid can be obtained by conditioning (i.e., unwinding, lengthening, or stretching) and ejecting a drag-reducing material, such as a polymer or other high molecular weight material, into the boundary layer. The efficacy of the ejected material is closely related to the hydration and shear stretching of the drag-reducing molecules immediately before ejection. The invention is a method and apparatus for creating a mixture/solution with optimal drag reduction characteristics. The device mixes a drag-reducing substance such as polymer powder, paste, solution or emulsion with a water flow, stretches the polymer molecules to improve hydration, and provides uniform vorticity to the mixture/solution before it is passed into an ejection system.Type: GrantFiled: December 31, 1998Date of Patent: March 13, 2001Assignee: Cortana CorporationInventor: Victor V. Babenko
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Patent number: 6138704Abstract: Skin friction reduction on a surface moving relative to a fluid can be obtained by ejecting a polymer-water mixture/solution into the boundary layer. The efficacy of the ejected polymer-water mixture/solution is closely related to polymer dissipation out of the boundary layer and conditioning (i.e, lengthening, unwinding or stretching) of the polymer molecules by liquid shear forces immediately before ejection. The invention is a method and apparatus for conditioning and ejecting a polymer-water mixture/solution that improves drag reduction characteristics of the mixture/solution and maintains the mixture/solution in the boundary layer for as long as possible. By improving the drag-reduction characteristics of the polymer-water mixture/solution and by extending the time it remains in the near-wall region, the ejector can increase the performance and reduce the volume and storage requirements of a drag-reduction system.Type: GrantFiled: December 31, 1998Date of Patent: October 31, 2000Assignee: Cortana CorporationInventor: Victor V. Babenko
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Patent number: RE41398Abstract: A method is provided to select appropriate material properties for turbulent friction drag reduction, given a specific body configuration and freestream velocity. The method is based on a mathematical description of the balance of energy at the interface between the viscoelastic surface and the moving fluid, and permits determination of the interaction of turbulent boundary layer fluctuations with a viscoelastic layer by solving two subtasks—i.e., a hydrodynamic problem and an elasticity problem, which are coupled by absorption and compliancy coefficients. Displacement, velocity, and energy transfer boundary conditions on a viscoelastic surface are determined, and a Reynolds stress type turbulence model is modified to account for redistribution of turbulent energy in the near-wall region of the boundary layer. The invention permits drag reduction by a coating with specified density, thickness, and complex shear modulus to be predicted for a given body geometry and freestream velocity.Type: GrantFiled: February 10, 2005Date of Patent: June 29, 2010Assignee: Cortana CorporationInventors: Carol L. May, Gennadiy A. Voropayev