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Turbulent Boundary Layer in High Rayleigh Number Convection in Air

du Puits, Ronald and Li, Ling and Resagk, Christian and Thess, André and Willert, Christian (2014) Turbulent Boundary Layer in High Rayleigh Number Convection in Air. Physical Review Letters, 112 (12), pp. 124301-1. American Physical Society. DOI: 10.1103/PhysRevLett.112.124301 ISSN 0031-9007

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Official URL: http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.112.124301

Abstract

Flow visualizations and particle image velocimetry measurements in the boundary layer of a Rayleigh-Bénard experiment are presented for the Rayleigh number Ra=1.4 x 10E10. Our visualizations indicate that the appearance of the flow structures is similar to ordinary (isothermal) turbulent boundary layers. Our particle image velocimetry measurements show that vorticity with both positive and negative sign is generated and that the smallest flow structures are 1 order of magnitude smaller than the boundary layer thickness. Additional local measurements using laser Doppler velocimetry yield turbulence intensities up to I=0.4 as in turbulent atmospheric boundary layers. From our observations, we conclude that the convective boundary layer becomes turbulent locally and temporarily although its Reynolds number Re≈200 is considerably smaller than the value 420 underlying existing phenomenological theories. We think that, in turbulent Rayleigh-Bénard convection, the transition of the boundary layer towards turbulence depends on subtle details of the flow field and is therefore not universal.

Item URL in elib:https://elib.dlr.de/88729/
Document Type:Article
Title:Turbulent Boundary Layer in High Rayleigh Number Convection in Air
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
du Puits, RonaldTechnische Universität IlmenauUNSPECIFIED
Li, LingTechnische Universität IlmenauUNSPECIFIED
Resagk, ChristianTechnische Universität IlmenauUNSPECIFIED
Thess, AndréTechnische Universität IlmenauUNSPECIFIED
Willert, Christianchris.willert (at) dlr.deUNSPECIFIED
Date:28 March 2014
Journal or Publication Title:Physical Review Letters
Refereed publication:Yes
Open Access:Yes
Gold Open Access:No
In SCOPUS:Yes
In ISI Web of Science:Yes
Volume:112
DOI :10.1103/PhysRevLett.112.124301
Page Range:pp. 124301-1
Publisher:American Physical Society
ISSN:0031-9007
Status:Published
Keywords:Rayleigh Benard convection, flow visualization, particle image velocimetry, transition to turbulence, boundary layer
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Aeronautics
HGF - Program Themes:Propulsion Systems (old)
DLR - Research area:Aeronautics
DLR - Program:L ER - Engine Research
DLR - Research theme (Project):L - Virtual Engine and Validation Methods (old)
Location: Köln-Porz
Institutes and Institutions:Institute of Propulsion Technology > Engine Measurement Systems
Deposited By: Willert, Dr.phil. Christian
Deposited On:05 May 2014 14:56
Last Modified:31 Jul 2019 19:45

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