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The evolution of the boundary layer in turbulent Rayleigh-Bénard convection in air

du Puits, Ronald and Willert, Christian (2016) The evolution of the boundary layer in turbulent Rayleigh-Bénard convection in air. Physics of Fluids, 28 (4), 044108. American Institute of Physics (AIP). DOI: 10.1063/1.4947261 ISSN 1070-6631

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Official URL: http://scitation.aip.org/content/aip/journal/pof2/28/4/10.1063/1.4947261

Abstract

We report measurements of the near-wall flow field in turbulent Rayleigh-Bénard convection in air (Pr = 0.7) using particle imagevelocimetry. The measurements were performed in a thin, rectangular sample at fixed Rayleigh number Ra = 1.45E10. In particular, we focus on the evolution of the boundary layer that a single convection roll generates along its path at the lower horizontal plate. We identify three specific flow regions along this path: (i) a region of wall-normal impingement of the down flow close to one corner of the sample, (ii) a region where a shear layer with almost constant thickness evolves, and (iii) a region in which this boundary layer grows and eventually detaches from the plate surface at the opposite corner of the sample. Our measurements with a spatial resolution better than 1/500 of the total thickness of the boundary layer show that the typical velocity field as well as its statistics qualitatively varies between the three flow regions. In particular, it could be verified that the shear layer region covering about 75% of the total area of the plate is in transition to turbulence at the Rayleigh number as low as investigated in the present work.

Item URL in elib:https://elib.dlr.de/104184/
Document Type:Article
Title:The evolution of the boundary layer in turbulent Rayleigh-Bénard convection in air
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
du Puits, RonaldTechnische Universität IlmenauUNSPECIFIED
Willert, ChristianChris.Willert (at) dlr.dehttps://orcid.org/0000-0002-1668-0181
Date:29 April 2016
Journal or Publication Title:Physics of Fluids
Refereed publication:Yes
Open Access:Yes
Gold Open Access:No
In SCOPUS:Yes
In ISI Web of Science:Yes
Volume:28
DOI :10.1063/1.4947261
Page Range:044108
Publisher:American Institute of Physics (AIP)
ISSN:1070-6631
Status:Published
Keywords:boundary layer turbulence, convection, laminar boundary layers, velocimetry, shear flows, particle image velocimetry, PIV, transition to turbulence
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Aeronautics
HGF - Program Themes:propulsion systems
DLR - Research area:Aeronautics
DLR - Program:L ER - Engine Research
DLR - Research theme (Project):L - Virtual Engine and Validation methods
Location: Köln-Porz
Institutes and Institutions:Institute of Propulsion Technology > Engine Measurement Systems
Deposited By: Willert, Dr.phil. Christian
Deposited On:09 Jun 2016 16:12
Last Modified:23 Jan 2020 04:20

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