Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.