Hostname: page-component-78c5997874-xbtfd Total loading time: 0 Render date: 2024-11-12T19:58:28.400Z Has data issue: false hasContentIssue false

On the evolution of thermally driven shallow cavity flows

Published online by Cambridge University Press:  26 April 2006

P. G. Daniels
Affiliation:
Department of Mathematics, City University, Northampton Square, London EC1V 0HB, UK
P. Wang
Affiliation:
Department of Mathematics, City University, Northampton Square, London EC1V 0HB, UK

Abstract

The temporal evolution of thermally driven flow in a shallow laterally heated cavity is studied for the nonlinear regime where the Rayleigh number R based on cavity height is of the same order of magnitude as the aspect ratio L (length/height). The horizontal surfaces of the cavity are assumed to be thermally insulating. For a certain class of initial conditions the evolution is found to occur over two non-dimensional timescales, of order one and of order L2. Analytical solutions for the motion throughout most of the cavity are found for each of these timescales and numerical solutions are obtained for the nonlinear time-dependent motion in end regions near each lateral wall. This provides a complete picture of the evolution of the steady-state flow in the cavity for cases where instability in the form of multicellular convection does not occur. The final steady state evolves on a dimensional timescale proportional to l2/κ, where l is the length of the cavity, κ is the thermal diffusivity of the fluid and the constant of proportionality depends on the ratio R/L.

Type
Research Article
Copyright
© 1994 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

Abramowitz, M. & Stegun, I. A. 1965 Handbook of Mathematical Functions. Dover.
Bejan, A. & Rossie, A. N. 1981 Natural convection in a horizontal duct connecting two fluid reservoirs. J. Heat Transfer 103, 108.Google Scholar
Boyack, B. E. & Kearney, D. W. 1972 Heat transfer by laminar natural convection in low aspect ratio cavities. ASME Paper 72-HT-2.
Brandt, A. 1977 Multi-level adaptive solutions to boundary-value problems. Math. Comput. 31, 333.Google Scholar
Cormack, D. E., Leal, L. G. & Imberger, J. 1974 Natural convection in a shallow cavity with differentially heated end walls. Part 1. Asymptotic theory. J. Fluid Mech. 65, 209.Google Scholar
Daniels, P. G. 1993 High Rayleigh number thermal convection in a shallow laterally heated cavity. Proc. R. Soc. Lond. A 440, 273.Google Scholar
Daniels, P. G., Blythe, P. A. & Simpkins, P. G. 1987 Onset of multicellular convection in a shallow laterally heated cavity. Proc. R. Soc. Lond. A 411, 327.Google Scholar
Gill, A. E. 1966 The boundary layer regime for convection in a rectangular cavity. J. Fluid Mech. 26, 515.Google Scholar
Hart, J. E. 1972 Stability of thin non-rotating Hadley circulations. J. Atmos. Sci. 29, 687.Google Scholar
Hart, J. E. 1983a Low Prandtl number convection between differentially heated end walls. Intl J. Heat Mass Transfer 26, 1069.Google Scholar
Hart, J. E. 1983b A note on the stability of low-Prandtl-number Hadley circulations. J. Fluid Mech. 132, 271.Google Scholar
Hurle, D. T. J., Jakeman, E. & Johnson, C. P. 1974 Convective temperature oscillations in molten gallium. J. Fluid Mech. 64, 565.Google Scholar
Ivey, G. N. 1984 Experiments on transient natural convection in a cavity. J. Fluid Mech. 144, 389.Google Scholar
Kuo, H. P. & Korpela, S. A. 1988 Stability and finite amplitude natural convection in a shallow cavity with insulated top and bottom and heated from a side. Phys. Fluids 31, 33.Google Scholar
Patterson, J. C. & Armfield, S. W. 1990 Transient features of natural convection in a cavity. J. Fluid Mech. 219, 469.Google Scholar
Patterson, J. C. & Imberger, J. 1980 Unsteady natural convection in a rectangular cavity. J. Fluid Mech. 100, 65.Google Scholar
Roache, P. J. 1976 Computational Fluid Dynamics. New Mexico: Hermosa.
Schladow, S. G., Patterson, J. C. & Street, R. L. 1989 Transient flow in a side-heated cavity at high Rayleigh number: a numerical study. J. Fluid Mech. 200, 121.Google Scholar
Wang, P. 1992 Thermal convection in slender laterally heated cavities. Ph.D. thesis, City University.
Wang, P. & Daniels, P. G. 1993 Numerical solutions for the flow near the end of a shallow laterally heated cavity. J. Engng Maths (to appear).Google Scholar