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Speakle measurements of convection in a liquid cooled from above

Published online by Cambridge University Press:  21 April 2006

R. Meynart ,
P. G. Simpkins  and
T. D. Dudderar
R. Meynart
Affiliation:
Service des Milieux Continus, Université Libre de Bruxelles, Belgium Present address: ACEC, 6000 Charleroi, Belgium.
P. G. Simpkins
Affiliation:
AT&T Bell Laboratories, Murray Hill, NJ 07974, USA
T. D. Dudderar
Affiliation:
AT&T Bell Laboratories, Murray Hill, NJ 07974, USA
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Abstract

Buoyancy-driven recirculation in a liquid-filled rectangular cavity cooled from above is shown to be locally modulated by an unstable thermal layer at the surface. Interferometric observations suggest that fluctuations that occur in a plume descending through the upper liquid layers are of the type described by Howard (1964) and by Krishnamurti & Howard (1981). Temperature measurements across the surface layer are in reasonable agreement with the diffusive heat-conduction model, but indicate that near the plume the fluid is cooler than elsewhere. Quasi-steady measurements of the velocity distribution in the upper regions of the cavity were made using multiple-exposure laser speckle velocimetry. Interrogation of the specklegrams with a Young's fringe technique yields a velocity-vector field of about two thousand elements. These data are used to calculate the corresponding velocity components and estimates of the vorticity distribution. The results compare favourably with measurements recorded directly from Fourier filtering methods.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 182 , September 1987 , pp. 235 - 254
Copyright
© 1987 Cambridge University Press

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References

Asundi, A. & Chiang, F. P. 1982 Theory and applications of the white-light speckle technique. Opt. Engng 21, 570.Google Scholar
Burch, J. M. & Tokarski, J. M. J. 1968 Production of multiple beam fringes from photographic scatterers. Optica Acta 15, 101.Google Scholar
Bryngdahl, O. 1965 Applications of shearing interferometry. Progress in Optics IV, p. 37. North-Holland.
Carslaw, H. S. & Jaeger, J. C. 1959 Conduction of Heat in Solids, chap. 2. Clarendon.
Elder, J. W. 1968 The unstable thermal interface. J. Fluid Mech. 32, 69.Google Scholar
Foster, T. D. 1965 Onset of convection in a layer of fluid cooled from above. Phys. Fluids 8, 1770.Google Scholar
Foster, T. D. & Waller, S. 1985 Experiments on convection of very high Rayleigh numbers. Phys. Fluids 28, 455.Google Scholar
Goodman, J. W. 1968 Introduction to Fourier Optics, chap. 7, p. 141. McGraw-Hill.
Howard, L. N. 1964 Convection at high Rayleigh number. In Proc. 11th Intl Cong. Appl. Mech., Munich (ed. H. Görtler), p. 1109. Springer.
Howard, L. N. & Krishnamurti, R. 1986 Large-scale flow in turbulent convection: a mathematical model. J. Fluid Mech. 170, 385.Google Scholar
Jaupart, C., Brandeis, G. & Allègre, C. J. 1984 Stagnant layers at the bottom of convecting magma chambers. Nature 308, 535.Google Scholar
Katsaros, K. B., Lui, W. T., Businger, J. A. & Tillman, J. E. 1977 Heat transport and thermal structure on the interfacial boundary layer measured in an open tank of water in turbulent free convection. J. Fluid Mech. 83, 311.Google Scholar
Krishnamurti, R. & Howard, L. N. 1981 Large-scale flow generation in turbulent convection. Proc. Natn. Acad. Sci. USA 78, 1981.Google Scholar
Lighthill, M. J. 1953 Theoretical considerations on free convection in tubes. Q. J. Mech. Appl. Maths 6, 398.Google Scholar
Lipson, S. G. & Lipson, H. 1969 Optical Physics, chap. 7. Cambridge Univesity Press.
Lourenco, L. M. & Whiffen, M. C. 1984 Laser speckle methods in fluid dynamics applications. In Proc. 2nd Intl Symp. on Applications of Laser Anemometry to Fluid Mech., Lisbon. Ladoan.
Meynart, R. 1980 Equal velocity fringes in a Rayleigh-Bénard flow by the speckle method. Appl. Optics 19, 1385.Google Scholar
Meynart, R. 1982 Convection flow field measurement by speckle velocimetry. Revue Phys. Appl. 17, 301.Google Scholar
Meynart, R. 1983a Mesure de champs de vitesse d’écoulements fluides par analyse de suites d'images obtenus par diffusion d'un feuillet lumineaux. Ph.D. thesis, Université Libre de Bruxelles.
Meynart, R. 1983b Instantaneous velocity field measurements in unsteady gas flow by speckle velocimetry. Appl. Optics 22, 535.Google Scholar
Miller, D. C. & Pernell, T. L. 1981 The temperature distribution in a simulated garnet Czochralski melt. J. Cryst. Growth 53, 523.Google Scholar
Oertel, H. & Bühler, K. 1978 A special differential interferometer used for heat convection investigations. Intl J. Heat Mass Transfer 21, 1111.Google Scholar
Pickering, C. J. D. & Halliwell, N. A. 1984 Speckle photography in fluid flows: signal recovery with two-step processing. Appl. Optics 23, 1128.Google Scholar
Simpkins, P. G. 1985 Convection in enclosures at large Rayleigh numbers. In Symp. on Stability in Convective Flows, 106th W A M, Miami, FL (ed. W. S. Saric & A. A. Szewczyk), p. 39. ASME.
Simpkins, P. G. & Dudderar, T. D. 1981 Convection in rectangular cavities with differentially heated end walls. J. Fluid Mech. 110, 433.Google Scholar
Spangenberg, W. G. & Rowland, W. R. 1961 Convective circulation in water induced by evaporative cooling. Phys. Fluids 4, 743.Google Scholar
Townsend, A. A. 1959 Temperature fluctuations over a heated horizontal surface. J. Fluid Mech. 5, 209.Google Scholar
Willis, G. E. & Deardorff, J. W. 1979 Laboratory observations of turbulent penetrative convection planforms. J. Geophys. Res. 84, 295.Google Scholar