New spatio-temporal instability scenarios in non-Boussinesq mixed convection

Suslov, Sergey A. (2007) New spatio-temporal instability scenarios in non-Boussinesq mixed convection. In: 60th Annual Meeting of the Divison of Fluid Dynamics, American Physical Society, 18-20 Nov 2007, Salt Lake City, Utah, USA.

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Abstract

[Abstract]: Mixed convection flows in a tall vertical channel with differentially heated walls subject to large cross-channel temperature gradients are shown to exhibit enormous variety of instability scenarios which have two physically distinct origins: the shear and the buoyancy of the flow. In order to visualize the most typical spatio-temporal patterns and complement previous analytical stability studies the Fourier integrals representing linearised disturbances arising from an initially localised source are evaluated numerically. The disturbance fields are obtained for strongly non-Boussinesq high-temperature convection of air. They are contrasted to their counterparts in the Boussinesq limits of small temperature gradients. A drastic difference in disturbance evolution scenarios is found. In particular, it is shown that non-Boussinesq natural convection is convectively unstable while mixed convection flows can be absolutely unstable. These scenarios are opposite to the ones detected in the classical Boussinesq convection in the same geometry.


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Item Type: Conference or Workshop Item (Commonwealth Reporting Category E) (Lecture)
Refereed: No
Item Status: Live Archive
Additional Information: Deposited in accordance with the copyright policy of the publisher. Copyright (c) 2007 American Physical Society.
Depositing User: Dr Sergey Suslov
Faculty / Department / School: Historic - Faculty of Sciences - Department of Maths and Computing
Date Deposited: 17 Apr 2008 00:26
Last Modified: 02 Jul 2013 23:01
Uncontrolled Keywords: non-Boussinesq convection; spatio-tempoeral instability
Fields of Research (FOR2008): 02 Physical Sciences > 0203 Classical Physics > 020303 Fluid Physics
URI: http://eprints.usq.edu.au/id/eprint/4071

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