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Investigation of the wake of low aspect ratio cylinders by tomographic PIV

Heine, Benjamin and Schanz, Daniel and Schröder, Andreas and Dierksheide, Uwe and Raffel, Markus (2011) Investigation of the wake of low aspect ratio cylinders by tomographic PIV. 9th International Symposium on Particle Image Velocimetry - PIV'11, 21. - 23. Jul. 2011, Kobe, Japan.

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Official URL: http://piv11.org/contact.html

Abstract

The wakes of wall mounted circular cylinders of very low aspect ratio have been investigated in a wind tunnel. Besides planar PIV, also high resolution tomographic PIV was used to capture the flow phenomena downstream of the cylinder. By changing the velocity U_inf and the cylinder height h at a constant aspect ratio h/D, a wide database of different flow conditions was obtained. The resulting relative height of the boundary layer thickness was between h/delta=0.6 and h/delta=2.5, while the Reynolds number based on the length l between leading edge and cylinder centre Re_l was between Re_l=57,000 and Re_l=188,000. A pair of counter-rotating vortices was found in the wake of the cylinder. The rotation sense is such, that in the center of the wake a positive vertical velocity component results. Also horseshoe vortices were found next to these trailing vortices. The relative height of the incoming boundary layer has a large impact on the development, strength and dissipation of the vortex system.

Document Type:Conference or Workshop Item (Speech, Paper)
Title:Investigation of the wake of low aspect ratio cylinders by tomographic PIV
Authors:
AuthorsInstitution or Email of Authors
Heine, Benjaminbenjamin.heine@dlr.de
Schanz, Danieldaniel.schanz@dlr.de
Schröder, Andreasandreas.schroeder@dlr.de
Dierksheide, Uweuwe.dierksheide@lavision.de
Raffel, Markusmarkus.raffel@dlr.de
Date:July 2011
Refereed publication:No
In ISI Web of Science:No
Number of Pages:5
Series Name:Conference Proceedings on USB-Stick
Status:Published
Keywords:Tomographic PIV, low aspect ratio cylinder, wake, dynamic stall
Event Title:9th International Symposium on Particle Image Velocimetry - PIV'11
Event Location:Kobe, Japan
Event Type:international Conference
Event Dates:21. - 23. Jul. 2011
Organizer:University of Tsukuba
HGF - Research field:Aeronautics, Space and Transport
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: Göttingen
Institutes and Institutions:Institute of Aerodynamics and Flow Technology > Helicopters
Institute of Aerodynamics and Flow Technology > Experimental Methods
Deposited By: Benjamin Heine
Deposited On:10 Oct 2011 11:07
Last Modified:12 Dec 2013 21:18

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