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Research Papers: Flows in Complex Systems

Effect of Gurney Flaps on an Elliptical Airfoil

[+] Author and Article Information
Lance W. Traub

Professor
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.

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References

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Figures

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Fig. 1

Model geometric details

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Fig. 2

Data repeatability and consistency

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Fig. 3

Effect of α on Cp traces, Re = 75,000

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Fig. 4

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

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Fig. 5

Observed separation locations for the clean airfoil

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Fig. 6

Effect of flap height and location on Cl

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Fig. 7

Effect of flap height and location on Cd

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Fig. 8

Effect of flap height and location on Cm

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Fig. 9

Summary plot of key performance parameters

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Fig. 10

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

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Fig. 11

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

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Fig. 12

Upper and lower surface lift and moment components

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