Multi-mode spatio-temporal instability in non-Boussinesq convection

Suslov, Sergey A. (2004) Multi-mode spatio-temporal instability in non-Boussinesq convection. ANZIAM Journal (Australian & New Zealand Industrial and Applied Mathematics Journal), 45(E). pp. 149-162. ISSN 1446-1811

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Abstract

It is shown that nonlinear (non-Boussinesq) fluid property variations caused by large temperature differences between the walls of a vertical channel are responsible for the appearance of physically distinct types of instability in mixed convection flows: the previously known shear and new buoyancy-induced instabilities. Shear instability dominates the forced convection regimes, while the buoyancy instability prevails in nearly natural convection states. The most challenging situation requiring elaborate theoretical analysis and numerical verification arises in a mixed convection regime where both instabilities compete, forming a wide variety of possible flow patterns. Each of the instabilities is found to undergo the transition from a convective state (when disturbances grow and propagate away from their source) to absolute (when disturbances grow and occupy the complete flow domain). A number of regions in a complete parameter space corresponding to qualitatively different flow scenarios are identified, and accurate boundaries separating them are computed. Various patterns are illustrated by the direct evaluation of the Fourier integrals representing disturbances.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Deposited in accordance with the copyright policy of the publisher. The official version is available from http://anziamj.austms.org.au/V45/CTAC2003/
Depositing User: Dr Sergey Suslov
Faculty / Department / School: Historic - Faculty of Sciences - Department of Maths and Computing
Date Deposited: 11 Oct 2007 01:10
Last Modified: 02 Jul 2013 22:45
Uncontrolled Keywords: non-Boussinesq convection
Fields of Research (FOR2008): 02 Physical Sciences > 0203 Classical Physics > 020303 Fluid Physics
09 Engineering > 0915 Interdisciplinary Engineering > 091501 Computational Fluid Dynamics
01 Mathematical Sciences > 0101 Pure Mathematics > 010106 Lie Groups, Harmonic and Fourier Analysis
Socio-Economic Objective (SEO2008): E Expanding Knowledge > 97 Expanding Knowledge > 970101 Expanding Knowledge in the Mathematical Sciences
URI: http://eprints.usq.edu.au/id/eprint/2584

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