Flow transitions in buoyancy-induced non-Darcy convection in a porous medium heated from below

Journal Article · Wed Aug 01 04:00:00 EDT 1990 · Journal of Heat Transfer (Transactions of the ASME (American Society of Mechanical Engineers), Series C); (United States)

DOI:https://doi.org/10.1115/1.2910440· OSTI ID:5233338

Kladias, N; Prasad, V ^[1]

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1. Columbia Univ., New York, NY (USA)

Thermoconvective instabilities in horizontal porous layers heated from below are studied numerically by employing the Brinkman-Forchheimer extended Darcy formulation. The onsets of stable and oscillatory convection are found to be strong functions of the governing parameters: fluid Rayleigh and Prandtl numbers, Darcy number, and conductivity ratio. The effects of porosity and specific heat ratio are pronounced only in the fluctuating convection regime. At the onset, the oscillatory convection is highly periodic, but with an increase in convective motions the disorder increases monotonically and the fluctuations become highly random. These results do not confirm the possibility of reverse transition from a more-disordered to a less-disordered state as predicted by the Darcy model (Kimura et al., 1986). The applicability of Darcy formulation is thus highly restrcited in the case of a Benard convection problem. In a randomly oscillating convective state, the heat transfer rate varies substantially with time.

• OSTI ID: 5233338
• Journal Information: Journal of Heat Transfer (Transactions of the ASME (American Society of Mechanical Engineers), Series C); (United States), Journal Name: Journal of Heat Transfer (Transactions of the ASME (American Society of Mechanical Engineers), Series C); (United States) Vol. 112:3; ISSN 0022-1481; ISSN JHTRA
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
420400* -- Engineering-- Heat Transfer & Fluid Flow
CONVECTION
DARCY LAW
ENERGY TRANSFER
HEAT TRANSFER
MASS TRANSFER
MATERIALS
MATHEMATICAL MODELS
POROUS MATERIALS