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Boundary layers and wind in cylindrical Rayleigh-B�©nard cells

Wagner, Sebastian and Shishkina, Olga and Wagner, Claus (2012) Boundary layers and wind in cylindrical Rayleigh-B�©nard cells. Journal of Fluid Mechanics, Vol. 6, pp. 336-366. Cambridge University Press. DOI: 10.1017/jfm.2012.69.

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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 Rayleighâ��B�©nard 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 ï¬�uctuations in the boundary layer region.

Document Type:Article
Additional Information:Published online: 06 March 20112
Title:Boundary layers and wind in cylindrical Rayleigh-B�©nard cells
Authors:
AuthorsInstitution or Email of Authors
Wagner, SebastianSebastian.Wagner@DLR.de
Shishkina, OlgaOlga.Shishkina@DLR.de
Wagner, ClausClaus.Wagner@DLR.de
Date:5 April 2012
Journal or Publication Title:Journal of Fluid Mechanics
Refereed publication:Yes
In Open Access:No
In SCOPUS:Yes
In ISI Web of Science:Yes
Volume:Vol. 6
DOI:10.1017/jfm.2012.69
Page Range:pp. 336-366
Publisher:Cambridge University Press
Status:Published
Keywords:Boundary layer structure, B�©nard convection, turbulent convection
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Aeronautics
HGF - Program Themes:Aircraft Research
DLR - Research area:Aeronautics
DLR - Program:L AR - Aircraft Research
DLR - Research theme (Project):L - Systems & Cabin
Location: Göttingen
Institutes and Institutions:Institute of Aerodynamics and Flow Technology > Fluid Systems
Deposited By: Sebastian Wagner
Deposited On:10 Apr 2012 14:31
Last Modified:12 Dec 2013 21:25

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