Hostname: page-component-cd9895bd7-gvvz8 Total loading time: 0 Render date: 2024-12-19T05:48:49.405Z Has data issue: false hasContentIssue false

A theoretical model for horizontal convection at high Rayleigh number

Published online by Cambridge University Press:  22 May 2007

G. O. HUGHES
Affiliation:
Research School of Earth Sciences, The Australian National University, Canberra, ACT 0200, Australia
R. W. GRIFFITHS
Affiliation:
Research School of Earth Sciences, The Australian National University, Canberra, ACT 0200, Australia
J. C. MULLARNEY
Affiliation:
Research School of Earth Sciences, The Australian National University, Canberra, ACT 0200, Australia Department of Oceanography, Dalhousie University, Halifax, NS, B3H 4J1, Canada

Abstract

We present a simple flow model and solution to describe ‘horizontal convection’ driven by a gradient of temperature or heat flux along one horizontal boundary of a rectangular box. Following laboratory observations of the steady-state convection, the model is based on a localized vertical turbulent plume from a line or point source that is located anywhere within the area of the box and that maintains a stably stratified interior. In contrast to the ‘filling box’ process, the convective circulation involves vertical diffusion in the interior and a stabilizing buoyancy flux distributed over the horizontal boundary. The stabilizing flux forces the density distribution to reach a steady state. The model predictions compare well with previous laboratory data and numerical solutions. In the case of a point source for the plume (the case which best mimics the localized sinking in the large-scale ocean overturning) the thermal boundary layer is much thicker than that given by the two-dimensional boundary layer scaling of H. T. Rossby (Tellus, vol. 50, 1965, p. 242).

Type
Papers
Copyright
Copyright © Cambridge University Press 2007

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

REFERENCES

Baines, W. D. 1985 Entrainment by a buoyant jet flowing along vertical walls. J. Hydraul. Res. 23, 221228.Google Scholar
Baines, W. D. & Turner, J. S. 1969 Turbulent buoyant convection from a source in a confined region. J. Fluid Mech. 37, 5180.Google Scholar
Beardsley, R. C. & Festa, J. F. 1972 A numerical model of convection driven by a surface stress and non-uniform heating. J. Phys. Oceanogr. 2, 444455.Google Scholar
Gill, A. E. 1982 Atmosphere–Ocean Dynamics. Academic.Google Scholar
Gregg, M. C. 1989 Scaling turbulent dissipation in the thermocline. J. Geophys. Res. 94, 96869698.Google Scholar
Hignett, P., Ibbetson, A. & Killworth, P. D. 1981 On rotating thermal convection driven by non-uniform heating from below. J. Fluid Mech. 109, 161187.Google Scholar
Houghton, J. T., MeiraFilho, L. G. Filho, L. G., Callander, B. A., Harris, N., Kattenberg, A. & Maskell, K. 1996 Climate Change 1995: The Science of Climate Change. Cambridge University Press.Google Scholar
Hughes, G. O. & Griffiths, R. W. 2006 A simple convective model of the global overturning circulation, including effects of entrainment into sinking regions. Ocean Modell. 12, 4679.Google Scholar
Jeffreys, H. T. 1925 On fluid motions produced by differences of temperature and humidity. Q. J. R. Met. Soc. 51, 347356.Google Scholar
Killworth, P. D. & Manins, P. C. 1980 A model of confined thermal convection driven by non-uniform heating from below. J. Fluid Mech. 98, 587607.Google Scholar
Killworth, P. D. & Turner, J. S. 1982 Plumes with time-varying buoyancy in a confined region. Geophys. Astrophys. Fluid Dyn. 20, 265291.Google Scholar
Ledwell, J. R., Watson, A. J. & Law, C. S. 1993 Evidence for slow mixing across the pycnocline from an open-ocean tracer release experiment. Nature. 364, 701703.Google Scholar
Linden, P. F. 1999 The fluid mechanics of natural ventilation. Annu. Rev. Fluid Mech. 31, 201238.Google Scholar
Manins, P. C. 1973 A filling box model of the deep circulation of the Red Sea. Mém. Soc. R. Sci. Liége. 6, 153166.Google Scholar
Manins, P. C. 1979 Turbulent buoyant convection from a source in a confined region. J. Fluid Mech. 91, 765781.CrossRefGoogle Scholar
Mullarney, J. C., Griffiths, R. W. & Hughes, G. O. 2004 Convection driven by differential heating at a horizontal boundary. J. Fluid Mech. 516, 181209.Google Scholar
Munk, W. H. 1966 Abyssal recipes. Deep-Sea Res. 13, 707730.Google Scholar
Munk, W. H. & Wunsch, C. 1998 Abyssal recipes II: energetics of tidal and wind mixing. Deep-Sea Res. I. 45, 19772010.Google Scholar
Paparella, F. & Young, W. R. 2002 Horizontal convection is non-turbulent. J. Fluid Mech. 466, 205214.Google Scholar
Peterson, W. H. 1979 A steady thermohaline convection model. PhD thesis, University of Miami.Google Scholar
Pierce, D. W. & Rhines, P. B. 1996 Convective building of a pycnocline: laboratory experiments. J. Phys. Oceanogr. 26, 176190.2.0.CO;2>CrossRefGoogle Scholar
Rossby, H. T. 1965 On thermal convection driven by non-uniform heating from below: an experimental study. Deep-Sea Res. 12, 916.Google Scholar
Rossby, H. T. 1998 Numerical experiments with a fluid non-uniformly heated from below. Tellus. 50, 242257.Google Scholar
Siggers, J. H., Kerswell, R. R. & Balmforth, N. J. 2004 Bounds on horizontal convection. J. Fluid Mech. 517, 5570.Google Scholar
Stommel, H. 1962 On the smallness of sinking regions in the ocean. Proc. Nat. Acad. Sci. Washington. 48, 766772.Google Scholar
Turner, J. S. 1973 Buoyancy Effects in Fluids. Cambridge University Press.Google Scholar
Turner, J. S. 1980 Differentiation and layering in magma chambers. Nature. 285, 213215.Google Scholar
Wang, W. & Huang, R. X. 2005 An experimental study on thermal convection driven by horizontal differential heating. J. Fluid Mech. 540, 4973.Google Scholar
Wong, A. B. D. & Griffiths, R. W. 2001 Stratification and convection produced by multiple plumes. Dyn. Atmos. Oceans. 30, 101123.Google Scholar