Aeronautics and astronautics – Aircraft structure – Details
Patent
1984-12-27
1987-11-17
Barefoot, Galen
Aeronautics and astronautics
Aircraft structure
Details
244200, 244199, 114 67R, 296 1S, 138 38, B64C 2110
Patent
active
047069104
ABSTRACT:
The invention is a system of flow control devices which result in reduced skin friction on aerodynamic and hydrodynamic surfaces. The devices cause a breakup of large-scale disturbances in the boundary layer of the flow field. Referring to FIGS. 1 and 2, the riblet device 10 acts to reduce disturbances near the boundary layer wall by the use of longitudinal striations forming vee-shaped grooves. These grooves are dimensional on the order of the wall vortices and turbulent burst dimensions 31 depicted in FIG. 3. The large-eddy breakup device 41, depicted in FIGS. 4 and 5, is a small strip or airfoil which is suspended in the upper region of the boundary layer. Various physical mechanisms cause a disruption of the large-scale vortices. The combination of the devices of this invention result in a substantial reduction in skin friction drag.
REFERENCES:
patent: 1152426 (1915-09-01), McCarroll
patent: 2573834 (1951-11-01), Davidson
patent: 2650752 (1953-09-01), Hoadley
patent: 3588005 (1971-06-01), Rethorst
patent: 4044797 (1977-08-01), Fujie et al.
patent: 4334658 (1982-06-01), MacKenzie
patent: 4354648 (1982-10-01), Schenk et al.
NASA Tech Brief, vol. 5, No. 2, "Grooves Reduce Aircraft Drag", 1980.
Anders John B.
Hefner Jerry N.
Walsh Michael J.
Barefoot Galen
Helfrich George F.
Manning John R.
The United States of America as represented by the Administrator
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