Aeronautics and astronautics – Aircraft sustentation – Sustaining airfoils
Patent
1996-06-14
1999-05-11
Jordan, Charles T.
Aeronautics and astronautics
Aircraft sustentation
Sustaining airfoils
244130, B64C21/10
Patent
active
059019280
ABSTRACT:
A method of disrupting a turbulent region of a boundary layer within a fluid flow passing over a surface to decrease momentum transfer, and thus friction drag, between the turbulent flow and the surface. Bending waves are generated on the surface to impose velocity and/or pressure oscillations within the turbulent region and disrupt the normal turbulent process within the boundary layer, thereby decreasing the transfer of momentum from the turbulent flow to the surface. The bending waves are preferably generated in a predominantly spanwise or normal direction relative to the streamwise fluid flow. In another embodiment, the bending waves enhance the turbulent process and increase the transfer of momentum between the turbulent flow and the surface. Bending wave actuators may bend the surface to generate bending waves within the surface itself. In another embodiment, actuators may generate bending waves within a separate material attached to the surface. Bending waves may also be generated within a laminar region of the boundary layer to trip the laminar region to turbulent flow and thereby energize the boundary layer.
REFERENCES:
patent: 3612446 (1971-10-01), Lebert
patent: 4170185 (1979-10-01), Murphy et al.
patent: 4516747 (1985-05-01), Lurz
patent: 4654546 (1987-03-01), Kirjavainen
patent: 4697769 (1987-10-01), Blackwelder et al.
patent: 4741498 (1988-05-01), Gerhardt
patent: 4885783 (1989-12-01), Whitehead et al.
patent: 4989810 (1991-02-01), Meier et al.
patent: 5114099 (1992-05-01), Gao
Riblets, chapter from, "Viscous Drag Reduction in Boundary Layers", Michael J. Walsh; vol. 123, Progress in Astronautics and Aeronautics.
"Compliant Wall-Turbulence Skin-Friction Reduction Research";Michael C. Fischer, Leonard M. Weinstein, Robert L. Ash and Dennis M. Bushnell; presented at the AIAA Eighth Fluid and Plasma Dynamics Conference.
"Suppression of Turbulence in Wall-Bounded Flows by High-Frequency Spanwise Oscillations"; W.J. Jung, N. Mangiavacchi and R. Akhaven; Phys. Fluids A 4(8); Aug. 1992.
"Turbulent Burst Control Through Phase-Locked Traveling Surface Depressions"; S.P. Wilkinson; R. Balasubramanian; presented at the AIAA Shear Flow Conference Mar. 12-14, 1985.
"Effect of Driven-Wall Motion on a Turbulent Boundary Layer" Leonard M. Weinstein; Reprinted from "Unsteady Turbulent Shear Flows"; 1981.
"Turbulence reduction in a Boundary Layer by a Local Spanwise Oscillating Surface", F. Laadhari and R. More; Phys. Fluids, vol. 6, No. 10; Oct. 1994 .
Aptek, Inc.
Jordan Charles T.
Ley John R.
Montgomery Christopher K.
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