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Three-Dimensional Flow Field Investigations of Flapping Wing Aerodynamics

Ehlers, Hauke and Konrath, Robert and Wokoeck, Ralf and Radespiel, Rolf (2016) Three-Dimensional Flow Field Investigations of Flapping Wing Aerodynamics. AIAA Journal, 54 (11), pp. 3434-3449. American Institute of Aeronautics and Astronautics (AIAA). DOI: 10.2514/1.J054488 ISSN 0001-1452

Full text not available from this repository.

Official URL: http://arc.aiaa.org/doi/10.2514/1.J054488

Abstract

Three-dimensional unsteady flow fields of a flapping, low-aspect-ratio wing have been investigated by means of highly resolved tomographic particle image velocimetry (Tomo-PIV) measurements and computational fluid dynamics (CFD). Furthermore, force measurements have been carried out. Tomo-PIV was applied to the flow above a flat plate wing during the downstroke. High spatial resolution and large volume thickness could be achieved by using sensitive sCMOS cameras and a traversing setup. The CFD calculations covered the complete period of motion. The analysis of the vortex-dominated flow fields provides a deeper understanding of vortex interaction and three-dimensionality of low Reynolds number (Re = 18;000 and Re = 36;000) flows. Two different Strouhal numbers (St = 0.06 and St = 0.13) are considered and their effects on the development of a leading edge and tip vortex are discussed. The PIV results show instantaneous flow fields after a leading edge separation that are dominated by small-scale turbulent vortex structures. The presented CFD approach is able to predict these vortices by using highly resolved meshes. Coarser grids compare well with the phase-averaged experimental flow fields, which feature multiple large-scale leading edge vortices developing during the downstroke. Turbulent effects decrease for the lower Reynolds number. Force and moment hystereses as well as large-scale leading edge vortice circulation, calculated from the PIV results, increase with increasing Strouhal number. Vortex breakdown of the wing tip vortex can be observed during the downstroke in the experimental data.

Item URL in elib:https://elib.dlr.de/96235/
Document Type:Article
Additional Information:November 2016, Published online: 26 July 2016
Title:Three-Dimensional Flow Field Investigations of Flapping Wing Aerodynamics
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Ehlers, Haukehauke.ehlers (at) dlr.deUNSPECIFIED
Konrath, Robertrobert.konrath (at) dlr.deUNSPECIFIED
Wokoeck, RalfTechnische Universität Braunschweig, Institut für StrömungsmechanikUNSPECIFIED
Radespiel, RolfTU BraunschweigUNSPECIFIED
Date:2016
Journal or Publication Title:AIAA Journal
Refereed publication:Yes
Open Access:No
Gold Open Access:No
In SCOPUS:Yes
In ISI Web of Science:Yes
Volume:54
DOI :10.2514/1.J054488
Page Range:pp. 3434-3449
Publisher:American Institute of Aeronautics and Astronautics (AIAA)
ISSN:0001-1452
Status:Published
Keywords:unsteady aerodynamics, low Reynolds number, Tomographic PIV, micro air vehicle
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Aeronautics
HGF - Program Themes:fixed-wing aircraft
DLR - Research area:Aeronautics
DLR - Program:L AR - Aircraft Research
DLR - Research theme (Project):L - Simulation and Validation
Location: Göttingen
Institutes and Institutions:Institute of Aerodynamics and Flow Technology > Experimental Methods
Deposited By: Micknaus, Ilka
Deposited On:26 Oct 2016 12:56
Last Modified:08 Mar 2018 18:42

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