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Experimental investigation of trailing-edge devices at transonic speeds

Published online by Cambridge University Press:  04 July 2016

K. Richter  and
H. Rosemann
K. Richter
Affiliation:
Institute of Arodynamics and Flow Technology, German Aerospace Center (DLR), Göttingen, Germany
H. Rosemann
Affiliation:
Institute of Arodynamics and Flow Technology, German Aerospace Center (DLR), Göttingen, Germany
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Abstract

The influence of trailing-edge devices such as Gurney flaps and divergent trailing edges of different height on the aerodynamic performance of an aerofoil at transonic speeds has been investigated experimentally. The investigation has been carried out in the Transonic Wind Tunnel Göttingen (TWG) using the two-dimensional aerofoil model VC-Opt at freestream Mach numbers of M ε [0.755, 0.775, 0.790] and a Reynolds number of Re = 5.0 x 106.

The results have shown that the trailing-edge devices increase the circulation of the aerofoil leading to a lift enhancement and pitching-moment decrease as well as an increase in minimum drag compared to the baseline configuration. The maximum lift-to-drag ratio is considerably improved and the onset of trailing-edge flow separation is shifted to higher lift. Besides the increased rear-loading, a downstream displacement of the shock provides the main lift enhancement in transonic flow.

The simple Gurney flap provides the largest additional circulation of all geometries tested. The smoother turning of the flow due to the additional ramp of the divergent trailing edge leads to a smaller increase of circulation. Slightly less lift but considerably less viscous (pressure) drag is generated enhancing the maximum lift-to-drag ratio compared to the Gurney flap. The negative affect of the Gurney flap on the pitching moment is also reduced.

For the high divergent trailing edges, different ramp slopes have a significant influence on the aerodynamic performance whereas at low device heights the influence is considerably diminished.

The results show that the divergent trailing edge proves to be the better trailing-edge device at transonic speeds. The application as an element for an adaptive wing is generally possible.

Type
Research Article
Information
The Aeronautical Journal , Volume 106 , Issue 1058 , April 2002 , pp. 185 - 193
Copyright
Copyright © Royal Aeronautical Society 2002 

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References

1. Birkemeyer, J. Drag minimization on a transonic wing by ventilation and adaptive contour bump, 1999, DLR FB 1999–28.Google Scholar
2. Knauer, A. Performance improvement of transonic airfoils through contour modifications in the shock region, 1998, DLR FB 1998–03.Google Scholar
3. Neuhart, D.H. and Penderoraft, O.C. A water tunnel study of Gurney flaps, 1988. NASA TM–4071.Google Scholar
4. Storms, B.L. and Jang, C.S. Lift enhancement of an airfoil using a Gurney flap and vortex generators, 1994, J Aircr, 31, (3), pp 542–547.Google Scholar
5. Giguère, P., Lemay, J. and Dumas, G. Gurney flap effects and scaling for low-speed airfoils, 1995, AIAA Paper 95-1881.Google Scholar
6. Jeffrey, D.R.M. and Hurst, D.W. Aerodynamics of the Gurney flap, 1996, AIAA Paper 96–2418.Google Scholar
7. Bloy, A.W., Tsioumanis, N. and Mellor, N.T. Enhanced aerofoil performance using small trailing-edge flaps, 1997, J Aircr, 34, (4), pp 569–571.Google Scholar
8. Jeffery, D., Zhang, X. and Hurst, D.W. Aerodynamics of Gurney flaps on a single-element high-lift wing, 2000, J Aircr, 37, (2), pp 295–301 Google Scholar
9. Ross, J.C., Storms, B.L. and Carrannanto, P.G. Lift-enhancing tabs on multielement airfoils, 1995, J Aircr, 32, (3), pp 649–655.Google Scholar
10. Papadakis, M., Myose, R.Y., Heron, I. and Johnson, B.L. An experimental investigation of Gurney flaps on a GA(W)–2 airfoil with 25% slotted flap, 1996, AIAA Paper 96–2437.Google Scholar
11. Myose, R., Papadakis, M. and Heron, I. Gurney flap experiments on airfoils, wings, and reflection plane model, 1998, J Aircr, 35, (2), pp 206–211.Google Scholar
12. Dodbele, S.S., Hobbs, C.R., Kern, T.A., Ghee, T.A., Hall, D.R. and Ely, W.L. Wind tunnel experiments and Navier-Stokes computations of a high-lift military airfoil, 1999, AIAA Paper 99–0540.Google Scholar
13. Mathias, D.L., Storms, B.L. and Ross, J.C. Lift-enhancing tabs on swept, three-dimensional high-lift systems, J Aircr, 35, (3), pp 494–495 Google Scholar
14. Buchholz, M.D. Lift augmentation on a delta wing via leading edge fences and the Gurney flap, 1992, NASA CR-194793.Google Scholar
15. Henne, P.A. and Gregg, R.D. New airfoil design concept, J of Aircr, 1991, 28, (5), pp 300–311.Google Scholar
16. Bechert, D.W., Meyer, R. and Hage, W. Drag reduction of airfoils with miniflaps. can we learn from dragonflies? 2000, AIAA Paper 2000–2315.Google Scholar
17. Kentfield, J.A.C. The potential of Gurney flaps for improving the aerodynamic performance of helicopter rotors, 1993, AIAA Paper 93–4883.Google Scholar
18. Richter, K. and Rosemann, H. Experimented Untersuchung am Profil VC-Opt mit Gumey-Klappen und divergenten Hinterkanten, 2001, Internal Report, DLR IB 223–2001 A 01, to be published.Google Scholar