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TECHNICAL PAPERS

Active Load Control for Airfoils using Microtabs

[+] Author and Article Information
D. T. Yen Nakafuji

New Technologies Engineering Division, Lawrence Livermore National Laboratory, P.O. Box 808, L-644, Livermore, CA 94551e-mail: nakafuji2@llnl.gov

C. P. van Dam

Department of Mechanical and Aeronautical Engineering, University of California at Davis, Davis, CA 95616e-mail: cpvandam@ucdavis.edu

R. L. Smith, S. D. Collins

Department of Electrical and Computer Engineering, University of California at Davis, Davis, CA 95616

J. Sol. Energy Eng 123(4), 282-289 (Jul 01, 2001) (8 pages) doi:10.1115/1.1410110 History: Received December 01, 2000; Revised July 01, 2001
Copyright © 2001 by ASME
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References

Wind Power Monthly, 2000, 16 , No. 1, p. 42.
Swisher,  R., 1998, “Windpower: A U.S. Perspective,” Wind Eng., 22, No. 4, pp. 185–188.
Twidell,  J., 1998, “Fundamentals of Wind Power Technology and Environmental Impact: An Educational Aid,” Wind Eng., 22, No. 5, pp. 235–241.
Committee of Assessment of Research Needs, 1991, Assessment of Research Needs for Wind Turbine Rotor Materials Technology, National Academy Press, Washington DC.
Stoddard, F. S., and Porter, B. K., 1986, “Wind Turbine Aerodynamics Research Needs Assessment,” DOE/ER/30075-H1.
Danish Wind Turbine Manufacturers Association website, www.windpower.dk
Liebeck,  R. H., 1978, “Design of Subsonic Airfoils for High Lift,” J. Aircr., 15, No. 9, pp. 547–561.
Bloy,  A. W., Tsioumanis,  N., and Mellor,  N. T., 1997, “Enhanced Aerofoil Performance using Small Trailing-Edge Flaps,” J. Aircr., 34, No. 4, pp. 569–571.
Storms,  B. L., and Jang,  C. S., 1994, “Lift Enhancement of an Airfoil using a Gurney Flap and Vortex Generators,” J. Aircr., 31, No. 3, pp. 542–547.
Ashby, D. L., 1996, “Effects of Lift-Enhancing Tabs on a Two-Element Airfoil,” Aerospace Eng., pp. 31–37.
Neuhart, D. H., 1988, “A Water Tunnel Study of Gurney Flaps,” NASA TM 4071.
Giguère,  P., Dumas,  G., and Lemay,  J., 1997, “Gurney Flap Scaling for Optimum Lift-to-Drag Ratio,” AIAA J., 35, No. 12, pp. 1888–1890.
Kentfield, J. A. C., 1994, “The Flow Over Gurney-Flaps, Devices for Improving Wind Turbine Performance,” Wind Power ’94, Minneapolis, May 1994, pp. 293–303.
Kentfield,  J. A. C., 1994, “Theoretically and Experimentally Obtained Performances of Gurney-Flap Equipped Wind Turbines,” ASME Wind Energy, Vol. 15, pp. 31–40.
Yen, D. T., van Dam, C. P., Bräuchle, F., Smith, R. L., and Collins, S. D., 2000, “Active Load Control and Lift Enhancement using MEM Translational Tabs,” AIAA Paper 2000–2422, June 2000.
Gonzalez,  C., Smith,  R. L., Howitt,  D. G., and Collins,  S. D., 1998, “MicroJoinery: Concept, Definition and Application to Microsystem Development,” Sens. Actuators A, 66, pp. 315–332.
Rogers,  S. E., and Kwak,  D., 1990, “An Upwind Differencing Scheme for the Time-Accurate Incompressible Navier-Stokes Equations,” AIAA J., 28, No. 2, pp. 253–262.
Rogers,  S. E., and Kwak,  D., 1991, “An Upwind Differencing Scheme for the Incompressible Navier-Stokes Equations,” Appl. Numer. Math., 8, No. 1, pp. 43–64.
Spalart, P. R., and Allmaras, S. R., 1994, “A One-Equation Turbulence Model for Aerodynamic Flows,” La Recherche Aérospatiale, No. 1, pp. 5–21
Kelling, F. H., 1968, “Experimental Investigation of a High-Lift Low-Drag Aerofoil,” Aeronautical Research Council CP 1187.
Galbraith,  R. A. McD., 1985, “The Aerodynamic Characteristics of a GU25-5(11)-8 Aerofoil for Low Reynolds Numbers,” Exp. Fluids, 3, pp. 253–256.
UC Davis Wind Tunnel Facility, http://windtunnel.engr.ucdavis.edu/
International Organization for Standardization, 1993, “Guide to the Expression of Uncertainty in Measurement,” Geneva, Switzerland.
Yen, D. T., 2001, “Active Load Control using Microtabs,” Ph.D. Dissertation, University of California at Davis.
Glasfaser Flugzeugbau Streifeneder GmBH website, http://www.streifly.de/
Shape Memory Alloy website, http://www.dynalloy.com/
Hackett,  J. E., 1996, “Tunnel-Induced Gradients and Their Effect on Drag,” AIAA J., 34, No. 12, pp. 2575–2581.
Van Dam,  C. P., 1999, “Recent Experience with Different Methods of Drag Prediction,” Prog. Aerosp. Sci., 35, pp. 751–798.
Vijgen, P. M. H. W., van Dam, C. P., Holmes, B. J., and Howard, F. G., 1989, “Wind Tunnel Investigations of Wings with Serrated Sharp Trailing Edges,” Low Reynolds Number Aerodynamics, Lecture Notes in Engineering, No. 54, T. J. Mueller (Ed.), Springer-Verlag, pp. 295–313.
Van Dam,  C. P., Yen,  D. T., and Vijgen,  P. M. H. W., 1999, “Gurney Flap Experiments on Airfoil and Wings,” J. Aircr., 36, No. 2, pp. 484–486.
Bechert, D. W., Meyer, R., and Hage, W., 2000, “Drag Reduction of Airfoils with Miniflaps. Can We Learn From Dragonflies?,” AIAA Paper 2000-2315, June.

Figures

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Translational microtab concept: a) Conventional versus translational microtab approach, b) predicted effect of microtab extension on lift
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Process flow for dovetail design used in microtabs
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Three-piece tab assembly consisting of a base, slider, and extender in a modular track assembly. Tab shown in 2-position ON (extended) and OFF (retracted) operation on airfoil pressure side.
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Comparison of present experimental results and computed Reynolds-averaged Navier-Stokes results (INS2D) with previously published results for the baseline airfoil at Re=0.63×106 and transition fixed at xtrans/c=0.455
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Computed streamlines based on Reynolds-averaged Navier-Stokes (INS2D) solution for airfoil with tab (h/c=0.01) at α=0°,Re=1.0×106,xtrans/c=0.455
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Computed surface pressure distributions data for baseline airfoil and airfoil with tabs (h/c=0.01) at the trailing edge and 5% from the trailing edge at α=0°,Re=1.0×106,xtrans/c=0.455
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Test model as mounted in the UC Davis Wind Tunnel Facility
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Wind tunnel testing process flow
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Comparison of present results and previously published results (Glasgow) for baseline airfoil at Re=0.63×106, boundary-layer trip at xtrans/c=0.455
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Installation of a) fixed tab at 10% from the trailing edge and b) remotely activated microtabs at 5% from the trailing edge
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a) Effect of tab height (tab at 5% from trailing edge) and b) effect of tab location (nominal tab height of 1%) on force coefficients for airfoil at α=0°,Re=1.0×106,xtrans/c=0.455
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Comparison of experimental and computed tab lift effectiveness at Re=1.0×106,xtrans/c=0.45. Tab at 5% from trailing edge with nominal tab height of 1%.
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Comparison of experimental and computed a) pitching moment coefficient and b) drag polar at Re=1.0×106,xtrans/c=0.455. Tab at 5% from trailing edge with nominal tab height of 1%
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Measured a) tab height effect (tab at 5% from trailing edge) and b) tab location effect (tab height of h/c=0.011) on lift coefficient at Re=1.0×106,xtrans/c=0.455
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Comparison of fixed (solid) tab effect and remotely activated tab (tab spacing s/h=0.5) effect of lift coefficient at Re=1.0×106,xtrans/c=0.455. Tabs at 5% from trailing edge with nominal tab height of 1%.

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