Hostname: page-component-78c5997874-m6dg7 Total loading time: 0 Render date: 2024-11-08T05:35:40.985Z Has data issue: false hasContentIssue false

The boundary correction for the Rayleigh-Darcy problem: limitations of the Brinkman equation

Published online by Cambridge University Press:  20 April 2006

D. A. Nield
Affiliation:
Department of Mathematics, University of Auckland, New Zealand

Abstract

The no-slip condition on rigid boundaries necessitates a correction to the critical value of the Rayleigh–Darcy number for the onset of convection in a horizontal layer of a saturated porous medium uniformly heated from below. It is shown that the use of the Brinkman equation to obtain this correction is not justified, because of the limitations of that equation. These limitations are discussed in detail. An alternative procedure, based on a model in which the porous medium is sandwiched between two fluid layers, and the Beavers–Joseph boundary condition is applied at the interfaces, is described, and an expression for the correction is obtained. It is found that the correction can be of either sign, depending on the relative magnitudes of the parameters involved.

Type
Research Article
Copyright
© 1983 Cambridge University Press

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Beavers, G. S. & Joseph, D. D. 1967 Boundary conditions at a naturally permeable wall J. Fluid Mech. 30, 197207.Google Scholar
Beavers, G. S., Sparrow, E. M. & Magnuson, R. A. 1970 Experiments on coupled parallel flows in a channel and a bounding porous medium. Trans. A.S.M.E. D: J. Basic Engng 92, 843848.Google Scholar
Beavers, G. S., Sparrow, E. M. & Masha, B. A. 1974 Boundary conditions at a porous surface which bounds a fluid flow A.I.Ch.E. J. 20, 596597.Google Scholar
Brinkman, H. C. 1947a A calculation of the viscous force exerted by a flowing fluid on a dense swarm of particles Appl. Sci. Res. A1, 2734.Google Scholar
Brinkman, H. C. 1947b On the permeability of media consisting of closely packed porous particles Appl. Sci. Res. A1, 8186.Google Scholar
Childress, S. 1972 Viscous flow past a random array of spheres J. Chem. Phys. 56, 25272539.Google Scholar
Elder, J. W. 1967 Steady free convection in a porous medium heated from below J. Fluid Mech. 27, 2948.Google Scholar
Happel, J. & Epstein, N. 1954 Cubical assemblages of uniform spheres Ind. Engng Chem. 46, 11871194.Google Scholar
Howells, I. D. 1974 Drag due to the motion of a Newtonian fluid through a sparse random array of small fixed rigid objects J. Fluid Mech. 64, 449475.Google Scholar
Jones, I. P. 1973 Low Reynolds number flow past a porous spherical shell Proc. Camb. Phil. Soc. 73, 231238.Google Scholar
Katto, Y. & Masuoka, T. 1967 Criterion for the onset of convective flow in a fluid in a porous medium Int. J. Heat Mass Transfer 10, 297309.Google Scholar
Levy, T. 1981 Loi de Darcy ou loi de Brinkman? C.R. Acad. Sci. Paris, Série II, 292, 872874.Google Scholar
Lundgren, T. S. 1972 Slow flow through stationary random beds and suspensions of spheres J. Fluid Mech. 51, 273299.Google Scholar
Masuoka, T. 1974 Convective currents in a horizontal layer divided by a permeable wall Bull. Japan Soc. Mech. Engrs 17, 232252.Google Scholar
Neale, G. & Nader, W. 1974 Practical significance of Brinkman's extension of Darcy's law: coupled parallel flows within a channel and a bounding porous medium. Can. J. Chem. Engng 52, 475478.CrossRefGoogle Scholar
Nield, D. A. 1977 Onset of convection in a fluid layer overlying a layer of a porous medium J. Fluid Mech. 81, 513522.Google Scholar
Nield, D. A. 1983 An alternative model for the wall effect in laminar flow of a fluid through a packed column. A.I.Ch.E. J. (to be published).Google Scholar
Richardson, S. 1971 A model for the boundary condition of a porous material. Part 2 J. Fluid Mech. 49, 327336.Google Scholar
Rudraiah, N., Veerappa, B. & BALACHANDRA RAO, S. 1980 Effects of nonuniform thermal gradient and adiabatic boundaries on convection in porous media Trans. A.S.M.E. C: J. Heat Transfer 102, 254260.Google Scholar
Saffman, P. G. 1971 On the boundary condition at the surface of a porous medium Stud. Appl. Math. 50, 93101.Google Scholar
Spielman, L. & Goren, S. L. 1968 Model for predicting pressure drop and filtration efficiency in fibrous media Environ. Sci. Tech. 2, 279287.Google Scholar
Tam, C. K. W. 1969 The drag on a cloud of spherical particles in low Reynolds number flow J. Fluid Mech. 38, 537546.Google Scholar
Taylor, G. I. 1971 A model for the boundary condition of a porous material. Part 1 J. Fluid Mech. 49, 319326.Google Scholar
Walker, K. & Homsy, G. M. 1977 A note on convective instability in Boussinesq fluids and porous media Trans. A.S.M.E. C: J. Heat Transfer 99, 338339.Google Scholar