Technical Brief

Effect of Trailing-Edge Flap Deflection on a Symmetric Airfoil Over a Wavy Ground

[+] Author and Article Information
V. Tremblay-Dionne, T. Lee

Department of Mechanical Engineering,
McGill University,
Montreal, QC H3A 2K6, Canada

1Corresponding author.

Contributed by the Fluids Engineering Division of ASME for publication in the JOURNAL OF FLUIDS ENGINEERING. Manuscript received July 28, 2018; final manuscript received October 8, 2018; published online December 12, 2018. Assoc. Editor: Moran Wang.

J. Fluids Eng 141(6), 064501 (Dec 12, 2018) (4 pages) Paper No: FE-18-1515; doi: 10.1115/1.4041736 History: Received July 28, 2018; Revised October 08, 2018

The effect of trailing-edge flap (TEF) deflection on the aerodynamic properties and flowfield of a symmetric airfoil over a wavy ground was investigated experimentally. This Technical Brief is a continuation of Lee and Tremblay-Dionne (2018, “Experimental Investigation of the Aerodynamics and Flowfield of a NACA 0015 Airfoil Over a Wavy Ground,” ASME J. Fluids Eng., 140(7), p. 071202) in which an unflapped airfoil was employed. Regardless of the flap deflection, the cyclic variation in the sectional lift Cl and pitching moment Cm coefficients over the wavy ground always persists. The Cm also has an opposite trend to Cl. The flap deflection, however, produces an increased maximum and minimum Cl and Cm with a reduced fluctuation compared to their unflapped counterparts. The Cd increase outperforms the Cl increase, leading to a lowered Cl/Cd of the flapped airfoil.

Copyright © 2019 by ASME
Topics: Deflection , Airfoils
Your Session has timed out. Please sign back in to continue.


Tomaru, H. , and Kohama, Y. , 1990, “ Experiments on Wing in Ground Effect With Fixed Ground Plates,” JSME-KSME Fluids Engineering Conference, Seoul, Korea, Oct. 11–13, pp. 370–373.
Hsiun, C. M. , and Chen, C. K. , 1996, “ Aerodynamic Characteristics of a Two-Dimensional Airfoil With Ground Effect,” J. Aircr., 33(2), pp. 386–392. [CrossRef]
Ahmed, M. R. , and Sharma, S. D. , 2005, “ An Investigation on the Aerodynamics of a Symmetric Airfoil in Ground Effect,” Exp. Therm. Fluid Sci., 29(6), pp. 633–647. [CrossRef]
Mahon, S. , and Zhang, X. , 2005, “ Computational Analysis of Pressure and Wake Characteristics of an Aerofoil in Ground Effect,” ASME J. Fluids Eng., 127(2), pp. 290–298. [CrossRef]
Ahmed, M. R. , Takasaki, T. , and Kohama, Y. , 2007, “ Aerodynamics of a NACA 4412 Airfoil in Ground Effect,” AIAA J., 45(1), pp. 37–47. [CrossRef]
Luo, S. C. , and Chen, Y. S. , 2012, “ Ground Effect on Flow Past a Wing With a NACA 0015 Cross-Section,” Exp. Therm. Fluid Sci., 40, pp. 18–28. [CrossRef]
Lee, T. , Majeed, A. , Siddiqui, B. , and Tremblay-Dionne, V. , 2018, “ Impact of Ground Proximity on the Aerodynamic Properties of an Unsteady Airfoil,” J. Aerosp. Eng., 232(10), pp. 1814–1830.
Tremblay-Dionne, V. , and Lee, T. , 2018, “ Ground Effect on the Aerodynamics of a NACA 0015 Airfoil With a Plain Trailing-Edge Flap,” Fluid Mech. Res. Int. J., 2(1), pp. 6–12.
Rozhdestvensky, K. V. , 2006, “ Wing-in-Ground Effect Vehicles,” Prog. Aerosp. Sci., 42(3), pp. 211–283. [CrossRef]
Morishita, E. , and Ashihara, K. , 1995, “ Ground Effect Calculation of a Two-Dimensional Airfoil Over a Wavy Surface,” Jpn. Soc. Aeronaut. Space Sci., 38(119), pp. 77–90.
Im, Y.-H. , and Chang, K.-S. , 2000, “ Unsteady Aerodynamics of a Wing-in-Ground-Effect Airfoil Flying Over a Wavy Wall,” J. Aircr., 37(4), pp. 690–696. [CrossRef]
Qu, Q. , Jia, X. , Wang, W. , Liu, P. , and Agarwal, R. K. , 2014, “ Numerical Study of the Aerodynamics of a NACA 4412 Airfoil in Dynamic Ground Effect,” Aerosp. Sci. Technol., 38, pp. 56–63. [CrossRef]
Matveev, K. I. , 2015, “ Heave and Pitch Motions of Wing-in-Ground Craft Flaying above Wavy Surface,” Front. Aerosp. Eng., 4(2), pp. 43–47. [CrossRef]
Lee, T. , and Tremblay-Dionne, V. , 2018, “ Experimental Investigation of the Aerodynamics and Flow Field of a NACA 0015 Airfoil Over a Wavy Ground,” ASME J. Fluids Eng., 40(1), p. 071202. [CrossRef]


Grahic Jump Location
Fig. 1

Schematic diagram of flapped airfoil and wavy ground. h and h′ indicate ground distance refers to unflapped and flapped airfoils, respectively. Measurement positions x0 and x10 correspond to wave peak and x5 corresponds to wave valley.

Grahic Jump Location
Fig. 2

Aerodynamic property over one wavelength at α = 8 deg. (a)–(d) flapped airfoil and (e)–(h) unflapped airfoil.

Grahic Jump Location
Fig. 3

Cp distribution as a function of measurement position: (a) flapped airfoil with h′/c = 5% and (b) unflapped airfoil with h/c = 5%

Grahic Jump Location
Fig. 4

Iso-u/U contours at wave peak (x0) and valley (x5) at selected wavy ground distances of (a)–(d) flapped airfoil, (e)–(h) unflapped airfoil, and (i)–(l) u/U velocity profiles at x0 and x5



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