DLR-Logo -> http://www.dlr.de
DLR Portal Home | Imprint | Contact | Deutsch
Fontsize: [-] Text [+]

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. Cambridge University Press. DOI: 10.1017/jfm.2012.69. ISSN 0022-1120.

[img] PDF - Registered users only - Requires a PDF viewer such as GSview, Xpdf or Adobe Acrobat Reader

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


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.

Document Type:Article
Additional Information:Published online: 06 March 20112
Title:Boundary layers and wind in cylindrical Rayleigh-Bénard cells
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 ISI Web of Science:Yes
Page Range:pp. 336-366
Publisher:Cambridge University Press
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: Sebastian Wagner
Deposited On:10 Apr 2012 14:31
Last Modified:17 Feb 2015 14:30

Repository Staff Only: item control page

Help & Contact
electronic library is running on EPrints 3.3.12
Copyright © 2008-2012 German Aerospace Center (DLR). All rights reserved.