<div class="csl-bib-body">
<div class="csl-entry">Mehl, F. (2019). <i>Turbulent drag reduction in channel flow with viscosity stratified fluids</i> [Diploma Thesis, Technische Universität Wien]. reposiTUm. https://doi.org/10.34726/hss.2019.59446</div>
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dc.identifier.uri
https://doi.org/10.34726/hss.2019.59446
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dc.identifier.uri
http://hdl.handle.net/20.500.12708/5348
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dc.description
Abweichender Titel nach Übersetzung der Verfasserin/des Verfassers
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dc.description.abstract
In this work, the turbulent flow of two immiscible fluids in a closed channel has been investigated. A thin layer of lubricating fluid (viscosity _1 ) flows on top of a thick layer of transported fluid (viscosity _2 ). The system has been analysed performing Direct Numerical Simulation (DNS) of the Navier-Stokes equations coupled with a Phase- Field Method (PFM) to describe the interfacial dynamics. The aim is to investigate the influence of the viscosity ratio = _1 /_2 (ratio between the viscosities of the two fluids) and of the Weber number W e = u_ h/ (ratio between inertial and surface tension forces) on the system behaviour. The setup consists of a thin lubricating layer (thickness t_1 = 0.15h) which flows on top of a thick layer (thickness t_2 = 1.85h) in a channel of total height 2h. Different combinations of the parameters have been considered, three viscosity ratios: = 1.00 (matched viscosity), = 0.50 and = 0.25 and three Weber numbers: We = 0.25 (higher surface tension), We = 0.50 and We = 1.00 (lower surface tension). The simulations are performed at a fixed shear Reynolds number Re_ = 300 and driving the flow along the streamwise direction with a constant mean pressure gradient. The simulation outcomes show that drag reduction (flow-rate increase) is obtained for all the six different cases considered. In particular, even when the matched viscosity case is considered a strong increase of the main layer flow-rate is observed. The analysis performed highlight two distinct drag reduction mechanisms: For the matched viscosity cases ( = 1), the drag reduction is directly linked to the laminarization of the thin lubricating layer, by opposite for the low viscosity cases ( < 1), turbulence can be sustained in the lubricating layer and drag reduction is achieved thanks to the low viscosity of the lubricating layer.
en
dc.language
English
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dc.language.iso
en
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dc.rights.uri
http://rightsstatements.org/vocab/InC/1.0/
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dc.subject
Direct Numerical Simulation (DNS)
en
dc.subject
Turbulence
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dc.subject
Multiphase
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dc.title
Turbulent drag reduction in channel flow with viscosity stratified fluids
en
dc.title.alternative
Turbulente Strömungswiderstandsreduzierung in Kanalströmung mit viskositätsgeschichteten Fluiden
de
dc.type
Thesis
en
dc.type
Hochschulschrift
de
dc.rights.license
In Copyright
en
dc.rights.license
Urheberrechtsschutz
de
dc.identifier.doi
10.34726/hss.2019.59446
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dc.contributor.affiliation
TU Wien, Österreich
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dc.rights.holder
Falk Mehl
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dc.publisher.place
Wien
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tuw.version
vor
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tuw.thesisinformation
Technische Universität Wien
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dc.contributor.assistant
Zonta, Francesco
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tuw.publication.orgunit
E322 - Institut für Strömungsmechanik und Wärmeübertragung
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dc.type.qualificationlevel
Diploma
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dc.identifier.libraryid
AC15329364
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dc.description.numberOfPages
52
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dc.identifier.urn
urn:nbn:at:at-ubtuw:1-122589
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dc.thesistype
Diplomarbeit
de
dc.thesistype
Diploma Thesis
en
dc.rights.identifier
In Copyright
en
dc.rights.identifier
Urheberrechtsschutz
de
tuw.advisor.staffStatus
staff
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tuw.assistant.staffStatus
staff
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item.languageiso639-1
en
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item.fulltext
with Fulltext
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item.openaccessfulltext
Open Access
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item.mimetype
application/pdf
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item.openairetype
master thesis
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item.grantfulltext
open
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item.openairecristype
http://purl.org/coar/resource_type/c_bdcc
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item.cerifentitytype
Publications
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crisitem.author.dept
E322 - Institut für Strömungsmechanik und Wärmeübertragung
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crisitem.author.parentorg
E300 - Fakultät für Maschinenwesen und Betriebswissenschaften