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Boundary layers and wind in cylindrical Rayleigh-Bénard cells

Wagner, Sebastian and Shishkina, Olga and Wagner, Claus (2012) Boundary layers and wind in cylindrical Rayleigh-Bénard cells. Journal of Fluid Mechanics, 697, pp. 336-366. Cambidge University Press. DOI: 10.1017/jfm.2012.69 ISSN 0022-1120

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Official URL: http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=8528002&fulltextType=RA&fileId=S0022112012000699

Abstract

We analyse the wind and boundary layer properties of turbulent Rayleigh–Bénard convection in a cylindrical container with aspect ratio one for Prandtl number Pr = 0.786 and Rayleigh numbers (Ra) up to 10^9 by means of highly resolved direct numerical simulations. We identify time periods in which the orientation of the large scale circulation (LSC) is nearly constant to be able to perform a statistical analysis of the LSC. The analysis is then reduced to two dimensions by considering only the plane of the LSC. Within this plane the large scale circulation is treated as a wind with thermal and viscous boundary layers developing close to the horizontal plates. Special focus is set on the spatial development of the wind magnitude and the boundary layer thicknesses along the bottom plate. A method for the local analysis of the instantaneous boundary layer thicknesses is introduced which shows a dramatically changing wind magnitude along the wind path. Furthermore a linear increase of the viscous and thermal boundary layer thickness along the wind is observed for all considered Ra while their ratio is spatially constant but depends weakly on Ra. A possible explanation is a strong spatial variation of the wind magnitude and fluctuations in the boundary layer region.

Item URL in elib:https://elib.dlr.de/71706/
Document Type:Article
Additional Information:Published online: 06 March 20112
Title:Boundary layers and wind in cylindrical Rayleigh-Bénard cells
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Wagner, SebastianSebastian.Wagner (at) DLR.deUNSPECIFIED
Shishkina, OlgaOlga.Shishkina (at) DLR.deUNSPECIFIED
Wagner, ClausClaus.Wagner (at) DLR.deUNSPECIFIED
Date:5 April 2012
Journal or Publication Title:Journal of Fluid Mechanics
Refereed publication:Yes
Open Access:No
Gold Open Access:No
In SCOPUS:Yes
In ISI Web of Science:Yes
Volume:697
DOI :10.1017/jfm.2012.69
Page Range:pp. 336-366
Publisher:Cambidge University Press
ISSN:0022-1120
Status:Published
Keywords:boundary layer structure, Bénard convection, turbulent convection
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Aeronautics
HGF - Program Themes:Aircraft Research (old)
DLR - Research area:Aeronautics
DLR - Program:L AR - Aircraft Research
DLR - Research theme (Project):L - Systems & Cabin (old)
Location: Göttingen
Institutes and Institutions:Institute of Aerodynamics and Flow Technology > Fluid Systems
Deposited By: Wagner, Sebastian
Deposited On:10 Apr 2012 14:31
Last Modified:08 Mar 2018 18:43

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