Research Papers: Flows in Complex Systems

Effect of Gurney Flaps on an Elliptical Airfoil

[+] Author and Article Information
Lance W. Traub

Aerospace and Mechanical
Engineering Department,
Embry Riddle Aeronautical University,
Prescott, AZ 86301
e-mail: traubl@erau.edu

Contributed by the Fluids Engineering Division of ASME for publication in the JOURNAL OF FLUIDS ENGINEERING. Manuscript received July 11, 2016; final manuscript received May 2, 2017; published online July 19, 2017. Assoc. Editor: Feng Liu.

J. Fluids Eng 139(10), 101102 (Jul 19, 2017) (9 pages) Paper No: FE-16-1437; doi: 10.1115/1.4037037 History: Received July 11, 2016; Revised May 02, 2017

A low-speed wind tunnel investigation is presented characterizing the impact of Gurney flaps on an elliptical airfoil. The chordwise attachment location and height of the flaps were varied, as was the Reynolds number. The results showed strong nonlinearities in the lift curve which were present for all tested geometries. Flap effectiveness was seen to diminish as the flap was moved closer to the trailing edge stemming from flap submersion in separated flow. For the tested cases, the measured lift coefficients showed a weak Re dependency. The upper airfoil surface was shown to carry approximately 80% of the total lift load. The top surface caused a pitching moment reversal associated with nonlinearity in the lift curve.

Copyright © 2017 by ASME
Your Session has timed out. Please sign back in to continue.


Lissaman, P. B. S. , 1983, “ Low-Reynolds-Number Airfoils,” Annu. Rev. Fluid Mech., 15(1), pp. 223–239. [CrossRef]
Weiburst, E. , Bertelrud, A. , and Ridder, S. O. , 1987, “ Experimental Investigation of Laminar Separation Bubbles and Comparison With Theory,” J. Aircr., 24(5), pp. 291–297. [CrossRef]
Hsiao, F. B. , and Hsu, C. C. , 1989, “ Numerical Prediction of Aerodynamic Performance for Low Reynolds Number Airfoils,” J. Aircr., 26(7), pp. 689–691. [CrossRef]
Roberts, W. B. , 1980, “ Calculation of Laminar Separation Bubbles and Their Effect on Airfoil Performance,” AIAA J., 18(1), pp. 25–31. [CrossRef]
Schmidt, G. S. , and Mueller, T. J. , 1989, “ Analysis of Low Reynolds Number Separation Bubbles Using Semiempirical Methods,” AIAA J., 27(8), pp. 993–1001. [CrossRef]
Gaster, M. , 1969, “ The Structure and Behavior of Laminar Separation Bubbles,” R&M No. 3595.
Horton, H. P. , 1968, “ Laminar Separation in Two and Three-Dimensional Incompressible Flow,” Ph.D. dissertation, University of London, London.
Lin, J. C. M. , and Pauley, L. L. , 1996, “ Low-Reynolds-Number Separation on an Airfoil,” AIAA J., 34(8), pp. 1570–1577. [CrossRef]
Lin, J. C. M. , and Pauley, L. L. , 1993, “ Unsteady Laminar Separation on Low-Reynolds-Number Airfoils,” AIAA Paper No. 93-0209.
Zahm, A. F. , Smith, R. H. , and Louden, F. A. , 1929, “ Forces on Elliptic Cylinders in Uniform Air Stream,” Aerodynamical Laboratory, Washington, DC, NACA Report No. NACA TR-315. https://ntrs.nasa.gov/search.jsp?R=19930091358
Schubauer, G. B. , 1939, “ Air Flow in the Boundary Layer on an Elliptic Cylinder,” National Advisory Committee for Aeronautics, Langley Aeronautical Laboratory, Langley Field, VA, NACA Report No. NACA-TR-652. https://ntrs.nasa.gov/search.jsp?R=19930091727
Hoerner, S. F. , and Borst, H. V. , 1975, Fluid-Dynamic Lift, S. F. Hoerner, New York, pp. 2.6–2.7.
Kwon, K. , and Park, S. O. , 2005, “ Aerodynamic Characteristics of an Elliptic Airfoil at Low Reynolds Number,” J. Aircr., 42(6), pp. 1642–1644. [CrossRef]
Chitta, V. , Dhakal, T. P. , and Walters, D. K. , 2012, “ Prediction of Aerodynamic Characteristics for Elliptic Airfoils in Unmanned Aerial Vehicle Applications,” Low Reynolds Number Aerodynamics and Transition, InTech, Rijeka, Croatia. [CrossRef]
Kwon, K. , and Park, S. O. , 2005, “ Aerodynamic Characteristics of an Elliptic Airfoil at Low Reynolds Number,” AIAA Paper No. 2005-4762.
Mitchell, C. A. , and Vogel, B. J. , 2003, “ The Canard Rotor Wing (CRW) Aircraft—A New Way to Fly,” AIAA Paper No. 2003-2517.
Liebeck, R. H. , 1978, “ Design of Subsonic Airfoils for High Lift,” J. Aircr., 15(9), pp. 547–561. [CrossRef]
Giguere, P. , Dumas, G. , and Lemay, J. , 1997, “ Gurney Flap Scaling for Optimum Lift-to-Drag Ratio,” J. Aircr., 35(12), pp. 1888–1890.
Maughmer, M. D. , and Bramesfeld, G. , 2008, “ Experimental Investigation of Gurney Flaps,” J. Aircr., 45(6), pp. 2062–2067. [CrossRef]
Traub, L. W. , and Agarwal, G. , 2007, “ Exploratory Investigation of Geometry Effects on Gurney Flap Performance,” J. Aircr., 44(1), pp. 351–353.
Meyer, R. , Hage, W. , and Bechert, D. W. , 2006, “ Drag Reduction on Gurney Flaps by Three-Dimensional Modifications,” J. Aircr., 43(1), pp. 132–140. [CrossRef]
Jeffrey, D. , Zhang, X. , and Hurst, D. W. , 2000, “ Aerodynamics of Gurney Flaps on a Single-Element High-Lift Wing,” J. Aircr., 37(2), pp. 295–301. [CrossRef]
Liu, T. , and Montefort, J. , 2007, “ Thin-Airfoil Theoretical Interpretation for Gurney Flap Lift Enhancement,” J. Aircr., 44(2), pp. 667–671. [CrossRef]
Traub, L. W. , 2009, “ Effect of Gurney Flap on Annular Wings,” J. Aircr., 46(3), pp. 1085–1088. [CrossRef]
Li, Y. , Wang, J. , and Zhang, P. , 2003, “ Influences of Mounting Angles and Locations on the Effects of Gurney Flaps,” J. Aircr., 40(3), pp. 494–498. [CrossRef]
Wang, J. J. , Lia, Y. C. , and Choi, K. S. , 2008, “ Gurney Flap—Lift Enhancement, Mechanisms and Applications,” Prog. Aerosp. Sci., 44(1), pp. 22–47. [CrossRef]


Grahic Jump Location
Fig. 1

Model geometric details

Grahic Jump Location
Fig. 2

Data repeatability and consistency

Grahic Jump Location
Fig. 3

Effect of α on Cp traces, Re = 75,000

Grahic Jump Location
Fig. 4

Surface skin friction patterns over clean airfoil, flow is left to right

Grahic Jump Location
Fig. 5

Observed separation locations for the clean airfoil

Grahic Jump Location
Fig. 6

Effect of flap height and location on Cl

Grahic Jump Location
Fig. 7

Effect of flap height and location on Cd

Grahic Jump Location
Fig. 8

Effect of flap height and location on Cm

Grahic Jump Location
Fig. 9

Summary plot of key performance parameters

Grahic Jump Location
Fig. 12

Upper and lower surface lift and moment components

Grahic Jump Location
Fig. 11

Effect of flap location on measured Cp, h/c = 0.04

Grahic Jump Location
Fig. 10

Dependence of Cdo and Clo on Re, α = 0 deg



Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In