Aeronautics and astronautics – Aircraft sustentation – Sustaining airfoils
Patent
1987-10-26
1990-06-12
Barefoot, Galen
Aeronautics and astronautics
Aircraft sustentation
Sustaining airfoils
244208, 244209, 244200, 244130, B64C 2102, B64C 2110
Patent
active
049326120
ABSTRACT:
A method and apparatus for reducing the skin friction on objects in relative motion to a field of fluid. The areas of relative low speed motion are fixed to align with a series of ridges on the surface of the object. The areas of low speed motion aligned with the ridges are removed by suction from the turbulent boundary layer which results in a reduction of drag on the object. An alternative embodiment injects fluid into areas of relative high speed between the ridges to reduce the shear and the drag caused by it. Selective suction and injection are combined in one apparatus in a second alternative embodiment. A fourth embodiment injects a polymeric solution to reduce drag. A fifth embodiment heats the fluid in specified areas to reduce drag. A sixth embodiment uses a compliant material in specified areas of the surface in contact with flowing fluid to reduce drag.
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Walsh, "Turbulent Boundary Layer Drag Reduction Using Riblets", AIAA Paper #82-0169, Jan. 11-14, 1982.
Gad-el-Hak & Blackwelder, A Drag Reduction Method for Turbulent Boundary Layers, 1987, AIAA-87-0358, pp. 1-12 (not prior art).
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Blackwelder Ron F.
Gad-el-Hak Mohamed
Barefoot Galen
Mollick Don R.
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