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Onset of oscillatory flows in double-diffusive convection

Ghorayeb, Kassem and Khallouf, Hicham and Mojtabi, Abdelkader Onset of oscillatory flows in double-diffusive convection. (1999) International Journal of Heat and Mass Transfer, 42 (4). 629-643. ISSN 0017-9310

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Official URL: http://doi.org/10.1016/S0017-9310(98)00204-X

Abstract

A numerical study is presented of unsteady double-diffusive convection in a square cavity with equal but opposing horizontal temperature and concentration gradients. The boundary conditions along the vertical side-walls are imposed in such a way that the buoyancy ratio N = GrS⧹GrT is equal to −1, where GrS and GrT are the solutal and thermal Grashof numbers, respectively. In this situation, steady-state convective flow is stable up to a threshold value Grc1 of the thermal Grashof number which depends on the Lewis number Le. Beyond Grc1, oscillatory convective flows occur. Here we study the transition, steady-state flow–oscillatory flow, as a function of the Lewis number. The Lewis number varies between 2 and 45. Depending on the values of the Lewis number, the oscillatory flow occurring for GrT slightly larger than Grc1 is either centro-symmetric ( for Le ⩾ 17) or asymmetric single frequency flow ( for Le ⩽ 17) . For larger values of the thermal Grashof number, the two regimes occur for fixed values of GrT and Le. Furthermore, computations show that Grc1 reaches a minimum equal to 4.75×104 for Le ≈ 7

Item Type:Article
HAL Id:hal-01886729
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - INPT (FRANCE)
Université de Toulouse > Institut National des Sciences Appliquées de Toulouse - INSA (FRANCE)
Other partners > Reservoir Engineering Research Institute - RERI (USA)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UPS (FRANCE)
Université de Toulouse > Université Toulouse 1 Capitole - UT1 (FRANCE)
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Deposited By: Isabelle Perez
Deposited On:25 Sep 2018 09:59

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