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Double-diffusive instability in an inclined fluid layer. Part 1. Experimental investigation

Published online by Cambridge University Press:  19 April 2006

R. C. Paliwal
Affiliation:
Department of Mechanical, Industrial and Aerospace Engineering, Rutgers University, New Brunswick, N.J. 08903 Present address: Electronic Associates, Inc., West Long Branch, N.J. 07764.
C. F. Chen
Affiliation:
Department of Mechanical, Industrial and Aerospace Engineering, Rutgers University, New Brunswick, N.J. 08903

Abstract

The stability boundary of a density-stratified fluid contained in an inclined slot subjected to a lateral temperature gradient was determined experimentally. The initial stratification due to salt was stable and linear in the vertical direction. Experiments were conducted in a 1·0 × 11.1 × 25·7 cm slot with the inclination angle θ from the vertical varying from −75° to + 75°. A positive angle denotes heating from the lower wall while a negative angle denotes heating from the upper wall. The temperature difference across the slot was increased slowly until the onset of instability was observed by means of a shadowgraph. The critical thermal Rayleigh number was found to be non-symmetrical with respect to θ = 0°, with heating of the upper wall less stable than heating of the lower wall. This is because there is a larger vertical solute gradient in the steady-state regime prior to the onset of instabilities when the lower wall is heated. The secondary flow consisting of horizontal convecting layers was very stable θ < 0° cases because of the stabilizing temperature effect. The motion of the layers when θ > 0° was quite vigorous. At θ = +75°, the secondary flow became unstable in a rather dramatic manner not observed heretofore.

Type
Research Article
Copyright
© 1980 Cambridge University Press

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References

Chen, C. F. 1975 Double-diffusive convection in an inclined slot. J. Fluid Mech. 72, 721729.Google Scholar
Chen, C. F. 1975 Double-diffusive instability in a density-stratified fluid along a heated inclined wall. J. Heat Transfer 100, 653658.Google Scholar
Chen, C. F., Briggs, D. G. & Wirtz, R. A. 1971 Stability of thermal convection in a salinity gradient due to lateral heating. Int. J. Heat Mass Transfer 14, 5765.Google Scholar
Chen, C. F., Paliwal, R. C. & Wong, S. B. 1976 Cellular convection in a density stratified fluid: Effect of inclination of the heated wall. Proc. 1976 Heat Transfer & Fluid Mech. Inst., pp. 1832. Stanford University Press.
Chen, C. F. & Sandford, R. D. 1976 Size and shapes of salt fingers near marginal state. J. Fluid Mech. 78, 601607.Google Scholar
Chen, C. F. & Sandford, R. D. 1977 Stability of time-dependent double-diffusive convection in an inclined slot. J. Fluid Mech. 83, 8395.Google Scholar
Chen, C. F. & Skok, M. W. 1974 Cellular convection in a salinity gradient along a heated inclined wall. Int. J. Heat Mass Transfer 17, 5160.Google Scholar
Weast, R. C. 1977–1978 Handbook of Chemistry and Physics, 58th edn, pp. D224225. Cleveland, Ohio: C.R.C.
Hart, J. E. 1971 On sideways diffusive instability. J. Fluid Mech. 49, 279288.Google Scholar
International Critical Tables of Numerical Data (1933), vol. II, p. 328. National Research Council; McGraw-Hill.
Kaufman, D. W. 1960 Sodium Chloride. New York: Reinhold.
Linden, P. F. & Weber, J. E. 1977 The formation of layers in a double-diffusive system with a sloping boundary. J. Fluid Mech. 81, 757773.Google Scholar
Paliwal, R. C. 1979 Double-diffusive convective instability in an inclined fluid layer. Ph.D. thesis, Department of Mechanical, Industrial and Aerospace Engineering, Rutgers University.
Paliwal, R. C. & Chen, C. F. 1980 Double-diffusive instability in an inclined fluid layer. Part 2. Stability analysis. J. Fluid Mech. 98, 769785.Google Scholar
Phillips, O. M. 1970 On flows induced by diffusion in a stably stratified fluid. Deep-Sea Res. 17, 435443.Google Scholar
Ruddick, B. R. & Shirtcliffe, T. G. L. 1979 Data for double diffusers (physical properties of aqueous salt-sugar solutions). Deep-Sea Res. 26, 775787.Google Scholar
Shirtcliffe, T. G. L. 1969 An experimental investigation of thermosolutal convection at marginal stability. J. Fluid Mech. 35, 677688.Google Scholar
Thorpe, S. A., Hutt, P. K. & Soulsby, R. 1969 The effect of horizontal gradients on thermohaline convection. J. Fluid Mech. 38, 375400.Google Scholar
Turner, J. S. & Chen, C. F. 1974 Two-dimensional effects in double-diffusive convection. J. Fluid Mech. 63, 577592.Google Scholar
Veronis, G. 1965 On finite amplitude instability in thermohaline convection. J. Mar. Res. 23, 117.Google Scholar
Wright, J. H. & Loehrke, R. I. 1976 The onset of thermohaline convection in a linearly stratified horizontal layer. J. Heat Transfer 98, 558563.Google Scholar