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PIV investigation of flow behind surface mounted permeable ribs

Panigrahi, Praditpa K. and Schröder, Andreas and Kompenhans, Jürgen (2005) PIV investigation of flow behind surface mounted permeable ribs. Experiments in Fluids, Vol. 40, pp. 277-300. Springer-Verlag GmbH. DOI: 10.1007/s00348-005-0067-8 ISSN 0723-4864 Paper

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The flow behind surface mounted permeable rib geometries, i.e. solid, slit, split-slit and inclined split-slit ribs have been studied using flow visualization and PIV (2-C and 3-C) technique in streamwise and cross-stream measurement planes. The objective behind this study is to understand the flow structures responsible for heat transfer/mixing enhancement with simultaneous pressure penalty reduction by permeable rib geometries. The Reynolds number based on the rib height has been set equal to 5,538 and the open area ratio of permeable ribs is equal to 20%. The permeable rib geometries have shorter reattachment length in comparison to the solid rib. The maximum 41% reduction in reattachment length is observed for the inclined split-slit rib. The splitter mounted inside the slit leads to two corner vortices behind it. The corner vortices drag the flow from the primary recirculation bubble region towards the rib resulting in drop of the reattachment length. Two horseshoe vortices are present in the flow through the slit at both sides of the splitter due to the upstream flow separation. The slit inclination moves these horseshoe vortices closer to the bottom wall. A film like flow through the slit is present near the downstream corner of the inclined split-slit rib. The spanwise velocity gradient due to the splitter leads to vorticity and turbulence enhancement by vortex stretching. The inclination of the slit and the use of a splitter inside the slit are two important design parameters responsible in generation of near-wall longitudinal vortices. The flow field behind permeable ribs is dominated by vortical structures with definable critical flow patterns, i.e. node, saddle and foci. These predominant swirling flow motions contribute to the mixing enhancement behind permeable rib geometries.

Item URL in elib:https://elib.dlr.de/21085/
Document Type:Article
Additional Information:Published online: 23. November 2005, 1432-114 (Online), Springer-Verlag
Title:PIV investigation of flow behind surface mounted permeable ribs
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Date:March 2005
Journal or Publication Title:Experiments in Fluids
Refereed publication:Yes
Open Access:No
Gold Open Access:No
In ISI Web of Science:Yes
Volume:Vol. 40
DOI :10.1007/s00348-005-0067-8
Page Range:pp. 277-300
Publisher:Springer-Verlag GmbH
ISSN:0723-4864 Paper
Keywords:flow visualization, PIV, Reynolds number
HGF - Research field:Aeronautics, Space and Transport (old)
HGF - Program:Aeronautics
HGF - Program Themes:Aircraft Research (old)
DLR - Research area:Aeronautics
DLR - Program:L AR - Aircraft Research
DLR - Research theme (Project):L - Flight Physics (old)
Location: Göttingen
Institutes and Institutions:Institute of Aerodynamics and Flow Technology > Experimental Methods
Deposited By: Micknaus, Ilka
Deposited On:19 Jun 2006
Last Modified:14 Jan 2010 20:38

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