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Thermosolutal convection in a solution with large negative Soret coefficient

Published online by Cambridge University Press:  29 March 2006

Douglas R. Caldwell
Affiliation:
School of Oceanography, Oregon State University, Corvallis

Abstract

The large negative Soret coefficient of 1N-LiI gives rise in a Rayleigh-Bénard experiment to a density distribution which is observed to stabilize the fluid layer for values of the Rayleigh number as large as 196 times the value of 1708 for the onset of convection in a pure fluid. The Soret transport also affects the convective heat flux. A power law relating heat flux and temperature difference is found with the same exponent as is found in pure fluids but with a lower value of the multiplicative constant. The Rayleigh number at the onset of power-law behaviour depends on the Soret coefficient. Three types of oscillation are seen: transient oscillations at onset, low frequency fluctuations at low Rayleigh number, and higher frequency oscillations similar to those observed in pure water. The intermediate state found after onset in NaCl solutions is not found in LiI.

Type
Research Article
Copyright
© 1976 Cambridge University Press

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References

Busse, F. H. 1967 Non-stationary finite-amplitude convection J. Fluid Mech. 28, 223239.Google Scholar
Busse, F. H. & Whitehead, J. A. 1974 Oscillatory and collective instabilities in large Prandtl number convection J. Fluid Mech. 66, 6779.Google Scholar
Caldwell, D. R. 1970 Nonlinear effects in a Rayleigh-Bénard experiment J. Fluid Mech. 42, 161175.Google Scholar
Caldwell, D. R. 1974 Experimental studies on the onset of thermohaline convection J. Fluid Mech. 64, 347367.Google Scholar
Caldwell, D. R. 1975 The Soret coefficient of LiI J. Phys. Chem. 79, 18821884.Google Scholar
Garon, A. M. & Goldstein, R. J. 1973 Velocity and heat transfer measurements in thermal convection Phys. Fluids, 16, 18181824.Google Scholar
Harp, E. J. & Hurle, D. T. J. 1968 Convective temperature oscillations in an unrotated Bénard cell Phil. Mag. 17, 10331038.Google Scholar
Hurle, D. T. J. & Jakeman, E. 1971 Soret-driven thermosolutal convection J. Fluid Mech. 47, 667687.Google Scholar
Hurle, D. T. J. & Jakeman, E. 1973 Natural oscillations in heated fluid layers. Phys. Lett A 43, 127130.Google Scholar
Krishnamurti, R. 1970 On the transition to turbulent convection. Part 2. The transition to time-dependent flow J. Fluid Mech. 42, 309320.Google Scholar
Legros, J. C., Platten, J. K. & Poty, P. G. 1972 Stability of a two-component fluid layer heated from below Phys. Fluids, 15, 13831390.Google Scholar
Legros, J. C., Rasse, D. & Thomas, G. 1970 Convection and thermal diffusion in a solution heated from below Chem. Phys. Lett. 4, 632634.Google Scholar
Platten, J. K. & Chavepeyer, G. 1972 Oscillations in a water-ethanol mixture heated from below. Phys. Lett A 40, 287288.Google Scholar
Rossby, H. T. 1969 A study of Bénard convection with and without rotation J. Fluid Mech. 36, 309335.Google Scholar
Silveston, P. L. 1958 Warmedurchgang in waagerechten Flussigkeitsschichten Forsch. Ing. Wes. 24, 29.Google Scholar
Veelarde, M. G. & Schecter, R. S. 1972 Thermal diffusion and convective stability Chem. Phys. Lett. 12, 312316.Google Scholar
Veronis, G. 1965 On finite amplitude instability in thermohaline convection J. Mar. Res. 23, 117.Google Scholar
Veronis, G. 1968 Effect of a stabilizing gradient of solute on thermal convection J. Fluid Mech. 34, 315336.Google Scholar
Willis, G. E. & Deardorff, J. W. 1967 Development of short-period temperature fluctuations in thermal convection Phys. Fluids, 10, 931937.Google Scholar