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Laminar free convection in confined regions

Published online by Cambridge University Press:  20 April 2006

M. Grae Worster
Affiliation:
D.A.M.T.P., Silver Street, Cambridge, CB3 9EW, England Current address: Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, U.S.A.
Alison M. Leitch
Affiliation:
R.S.E.S., Australian National University, G.P.O. Box 4, Canberra A.C.T. 2601, Australia Current address: Erindale Campus, University of Toronto, Mississauga, Ontario, Canada L5L IC6.

Abstract

We investigate the development of density stratification in a confined fluid due to a buoyancy source which gives rise to a vertical convective boundary layer. We find that the stratification is significantly different when the boundary layer is laminar rather than turbulent. In particular, the magnitude of the density gradient in the fluid interior increases rather than decreases in the direction of flow of the boundary layer, and this density gradient varies smoothly so that there is no density front between the stratified fluid and the unmodified homogeneous fluid. Laboratory experiments are described in which homogeneous fluid in a rectangular container was heated at a vertical sidewall. Vertical temperature profiles and streak photographs were taken which show the dominant features of the stratification mechanism under laminar flow conditions. We review similarity theory for a vertical, laminar, free-convection boundary layer in a homogeneous environment, and develop new similarity solutions for convective boundary layers in stratified environments. We use these analytic results to interpret qualitative features of the experimentally observed flow fields and to develop an expression for the depth of the stratified layer as a function of time.

Type
Research Article
Copyright
© 1985 Cambridge University Press

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References

Baines, W. D. & Turner, J. S. 1969 Turbulent buoyant convection from a source in a confined region. J. Fluid Mech. 37, 5180.Google Scholar
Chen, C. F. & Turner, J. S. 1980 Crystallization in a double-diffusive system. J. Geophys. Res. 85, 25732593.Google Scholar
Elder, J. W. 1965 Turbulent free convection in a vertical slot. J. Fluid Mech. 23, 99111.Google Scholar
Germeles, A. E. 1975 Forced plumes and mixing of liquids in tanks. J. Fluid Mech. 71, 601623.Google Scholar
Gill, A. E. 1966 The boundary-layer regime for convection in a rectangular cavity. J. Fluid Mech. 26, 515536.Google Scholar
Hieber, C. A. & Gebhart, B. 1971 Stability of vertical natural convection boundary layers: expansion at large Prandtl number. J. Fluid Mech. 49, 577591.Google Scholar
Horne, E. P. W. & Toole, J. M. 1980 Sensor response mismatches and lag correction techniques for temperature-salinity profilers. J. Phys. Oceanogr. 10, 11221130.Google Scholar
Killworth, P. C. 1977 Mixing on the Weddell Sea continental slope. Deep-Sea Res. 36, 427448.Google Scholar
Kuiken, H. K. 1968 An asymptotic solution for large Prandtl number free convection. J. Engng Maths 2, 355371.Google Scholar
Leitch, A. M. 1985 Laboratory models of magma chambers. Ph.D. thesis, Australian National University, Canberra.
Mcbirney, A. R. 1980 Mixing and unmixing of magmas. J. Volcanol. Geotherm. Res. 7, 357371.Google Scholar
Ostrach, S. 1964 Laminar flows with body forces. In Theory of Laminar Flows (ed. F. K. Moore). Princeton University Press.
Patterson, J. & Imberger, J. 1980 Unsteady natural convection in a rectangular cavity. J. Fluid Mech. 100, 6586.Google Scholar
Schwind, R. G. & Vliet, G. C. 1964 Observations and interpretations of natural convection and stratification in vessels. Proc. Heat Trans. and Fluid Mech. Inst. 51–68.
Segur, J. B. 1953 Physical properties of glycerol and its solutions. In Glycerol (ed. C. S. Miner & N. N. Dalton). American Chemical Society Monograph Series.
Sparks, R. S. J., Meyer, P. & Sigurdsson, H. 1980 Density variations amongst mid-ocean ridge basalts: implications for magma mixing and the scarcity of primitive lavas. Earth Planet. Sci. Letter 46, 419430.Google Scholar
Sparrow, E. M. & Greg, J. L. 1956 Laminar free convection from a vertical plate with uniform surface heat flux. Trans. A.S.M.E.
Turner, J. S. 1979 Buoyancy Effects in Fluids. Cambridge University Press.
Worster, M. G. 1983 Convective flow problems in geological fluid mechanics. Ph.D. thesis, University of Cambridge.
Worster, M. G. & Huppert, H. E. 1983 Time-dependent density profiles in a filling box. J. Fluid Mech. 132, 457466.Google Scholar