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Experimental investigation of trailing-edge devices at transonic speeds

Richter, K. and Rosemann, H. (2001) Experimental investigation of trailing-edge devices at transonic speeds. Aerodynamics Conference 2001, Royal Aeronautical Society, London, UK. 9.-10. April 2001.

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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 airfoil at transonic speeds has been investigated experimentally. The investigation has been carried out in the Transonic Wind Tunnel Göttingen (TWG) using the two-dimensional airfoil model VC-Opt at freestream Mach numbers of M element of [0.755, 0.775, 0.790] and a Reynolds number of Re = 5.0 · 10 6. The results have shown that the trailing-edge devices increase the circulation of the airfoil 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.

Document Type:Conference or Workshop Item (Speech)
Additional Information: LIDO-Berichtsjahr=2002,
Title:Experimental investigation of trailing-edge devices at transonic speeds
Authors:
AuthorsInstitution or Email of Authors
Richter, K.UNSPECIFIED
Rosemann, H.UNSPECIFIED
Date:2001
Status:Published
Keywords:two-dimensional airfoil VC-Opt, experimental investigation, trailing
Event Title:Aerodynamics Conference 2001, Royal Aeronautical Society, London, UK. 9.-10. April 2001
Organizer:Royal Aeronautical Society
HGF - Research field:Aeronautics, Space and Transport (old)
HGF - Program:Aeronautics
HGF - Program Themes:Aircraft Research
DLR - Research area:Aeronautics
DLR - Program:L AR - Aircraft Research
DLR - Research theme (Project):L - Flight Physics
Location: Köln-Porz , Braunschweig , Göttingen
Institutes and Institutions:Institute of Aerodynamics and Flow Technology
Deposited By: elib DLR-Beauftragter
Deposited On:31 Jan 2006
Last Modified:14 Jan 2010 19:02

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