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Transitional flow structures downstream of a backward-facing-step – An investigation using high resolution tomo PIV

Schröder, Andreas and Schanz, Daniel and Heine, Benjamin and Dierksheide, Uwe (2011) Transitional flow structures downstream of a backward-facing-step – An investigation using high resolution tomo PIV. 9th International Symposium on Particle Image Velocimetry – PIV11, 21. - 23. Jul. 2011, Kobe, Japan.

Full text not available from this repository.

Official URL: http://piv11.org/

Abstract

Transitional flow structures in the shear layer of a laminar separation bubble downstream of a backward facing step (BFS) have been investigated by means of 2D-2C- und highly resolved 3D-3C- tomographic Particle Image Velocimetry (PIV) for Reynolds numbers between Re = 1420 and 3000 based on free-stream velocity U and step height h. By using an external acoustic excitation of the shear layer it was possible to arrange phase locked measurements of the wavy flow structures which emanate from instabilities according to Kelvin-Helmholtz (KH). Snapshots of fully 3D-3C velocity vector volumes show complex flow topologies of the non-linear part of the laminar-turbulent transition scenario. This part seems to be governed by hairpin-like, streamwise elongated vortices on top of the classical spanwise oriented 2- D waves. These vortices organize a rapid fluid exchange normal to the shear layer leading to turbulent reattachment of the flow and subsequent development of a turbulent boundary layer.

Document Type:Conference or Workshop Item (Speech, Paper)
Title:Transitional flow structures downstream of a backward-facing-step – An investigation using high resolution tomo PIV
Authors:
AuthorsInstitution or Email of Authors
Schröder, AndreasUNSPECIFIED
Schanz, DanielUNSPECIFIED
Heine, BenjaminUNSPECIFIED
Dierksheide, UweLaVision, Göttingen
Date:2011
Refereed publication:No
In SCOPUS:No
In ISI Web of Science:No
Series Name:Conference Proceedings on USB-Stick
Status:Published
Keywords:backward facing step (BFS), Particle Image Velocimetry (PIV), tomo PIV, CCD camera, velocity vector fields
Event Title:9th International Symposium on Particle Image Velocimetry – PIV11
Event Location:Kobe, Japan
Event Type:international Conference
Event Dates:21. - 23. Jul. 2011
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: Ilka Micknaus
Deposited On:19 Aug 2011 08:23
Last Modified:15 Dec 2011 15:26

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