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Coherent Structures in Critical Wing Flows

Kreplin, Hans-Peter and Kindler, Kolja and Ronneberger, Dirk (2004) Coherent Structures in Critical Wing Flows. 12th International Symposium „Application of laser techniques to fluid mechanics“, 2004-07-12 - 2004-07-15, Lissabon, Portugal.

Full text not available from this repository.

Official URL: http://in3.dem.ist.utl.pt/lxlaser2004

Abstract

The study is concerned with the analysis of the turbulent flow detached from an unswept wing at large angles of attack. The transition regime between subcritical and supercritical separation, which is well known to delimit the low Reynolds number regime, is in the focus of the investigation. The coherent structures that develop with trailing edge separation are extracted from Particle Image Velocimetry (PIV) data by means of Proper Orthogonal Decomposition (POD). Thus, the three-dimensionality of the flow in terms of spanwise morphology is studied, and a reduced representation by (geometrical) symmetry plane investigation turns out to be justified. Additionally, fluctuations of the flow velocity and the wall pressure exhibit an interval of characteristic, preferred length scales of the vortical structures. The decomposition of both the separation scenarios, inspecting the suction side of the wing and the near wake flow, yields to a qualitative identification of the large-scale structure. Moreover, POD dissects the vortical motion according to the energy contained in the various modes, and thus with respect to the respective impact on flow dynamics. These insights into coherent structures, and the characterization of their dynamics is beneficial particularly to the basic validation of Large Eddy Simulations (LES) of such complex flows.

Document Type:Conference or Workshop Item (Speech, Paper)
Title:Coherent Structures in Critical Wing Flows
Authors:
AuthorsInstitution or Email of Authors
Kreplin, Hans-PeterUNSPECIFIED
Kindler, KoljaUNSPECIFIED
Ronneberger, DirkUni Göttingen
Date:2004
Status:Published
Keywords:airfoil, separation, coherent structures, PIV, POD
Event Title:12th International Symposium „Application of laser techniques to fluid mechanics“
Event Location:Lissabon, Portugal
Event Type:international Conference
Event Dates:2004-07-12 - 2004-07-15
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 -- no assignement
Location: Göttingen
Institutes and Institutions:Institute of Aerodynamics and Flow Technology > Helicopters
Deposited By: Elisabeth Senger
Deposited On:15 Feb 2006
Last Modified:27 Apr 2009 05:00

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