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An experimental study of laminar plumes

Published online by Cambridge University Press:  26 April 2006

Elisha Moses
Affiliation:
The James Franck and Enrico Fermi Institutes, The University of Chicago, 5640 S. Ellis Ave., Chicago, IL 60637, USA Present address: Department of Physics, Weizmann Institute, Rehovot 76100, Israel.
Giovanni Zocchi
Affiliation:
The James Franck and Enrico Fermi Institutes, The University of Chicago, 5640 S. Ellis Ave., Chicago, IL 60637, USA Present address: Ecole Normale Superieure, 24 rue Lhomond, 75005 Paris, France.
Albert Libchaberii
Affiliation:
The James Franck and Enrico Fermi Institutes, The University of Chicago, 5640 S. Ellis Ave., Chicago, IL 60637, USA Present address: Department of Physics, Princeton University, Princeton. NJ 08544, USA.

Abstract

We present an experimental study of the scaling laws for the front (or cap) of an isolated, laminar starting plume. The scaling relations are formulated and measured experimentally over a range of power, fluids, and heaters. The results are that the cap rises at constant velocity, grows diffusively in width, and its temperature depends inversely on height. This extends analytic results by Batchelor (1954) for the column (stem) below the front. The source size determines initial conditions for the cap, but does not affect it in the far field. The shape of the front is fitted by a model of potential flow. The interaction between plume caps is complex, but with simple underlying dynamics. We conjecture that some of our conclusions can be applied to a distribution of plumes, as in soft turbulent convection.

Type
Research Article
Copyright
© 1993 Cambridge University Press

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References

Aref, H. & Tryggvason, G. 1989 Model of Rayleigh Taylor instability. Phys. Rev. Lett. 62, 749752.Google Scholar
Barenblatt, G. I. 1979 Similarity, Self Similarity and Intermediate Asymptotics (translated by N. Stein; ed. M. Van Dyke). Plenum.
Batchelor, G. K. 1954 Heat convection and buoyancy effects in fluids. Q. J. R. Met. Soc. 80, 339358.Google Scholar
Castaing, B., Gunaratne, G., Heslot, F., Kadanoff, L., Libchaber, A., Thomae, S., Wu, X. Z., Zaleski, S. & Zanetti, G. 1989 Scaling of hard thermal turbulence in Rayleigh-Bénard convection. J. Fluid Mech. 204, 130.Google Scholar
Chu, T. Y. & Goldstein, J. R. 1973 Turbulent convection in a horizontal layer of water. J. Fluid Mech. 60, 141159.Google Scholar
Fujii, T. 1963 Theory of the steady laminar natural convection above a horizontal line heat source and a point heat source. Intl J. Heat Mass Transfer 6, 597606.Google Scholar
Fujii, T., Morioka, I. & Uehara, U. 1973 Buoyant plume above a horizontal line heat source. Intl J. Heat Mass Transfer 16, 755768.Google Scholar
Gebhart, B., Jaluria, Y., Mahanjan, R. L. & Sammakia, B. 1988 Buoyancy Induced Flows and Transport. Hemisphere.
Gebhart, B., Pera, L., Schorr, A. W. 1970 Steady laminar natural convection plumes above a horizontal line heat source. Intl J. Heat Mass Transfer 13, 161171.Google Scholar
Heslot, F., Castaing, B. & Libchaber, A. 1987 Transition to turbulence in helium gas. Phys. Rev. A 36, 58705873.Google Scholar
Lighthill, M. J. 1986 An Informal Introduction to Theoretical Fluid Mechanics. Oxford University Press.
Morton, B. R., Taylor, G. I. & Turner, J. S. 1956 Turbulent gravitational convection form maintained and instantaneous sources. Proc. R. Soc. Land. A 234, 123.Google Scholar
Moses, E., Zocchi, G., Procaccia, I. & Libchaber, A. 1991 The dynamics and interaction of laminar thermal plumes. Europhys. Lett. 14, 5560.Google Scholar
Neumann, J. von 1941 NDRC, Div. B, Rep. AM-9, June 30, 1941.
Neumann, J. von 1947 The point source solution. Los Alamos Rep. LA-2000, pp. 2755.
Pera, L. & Gebhart, G. 1971 On the stability of laminar plumes: some numerical solutions and experiments. Intl J. Heat Mass Transfer 14, 975984.Google Scholar
Pera, L. & Gebhart, B. 1975 Laminar plume interactions. J. Fluid Mech. 68, 259271.Google Scholar
Polymeropoulos, C. E. & Gebhart, B. 1967 Incipient instability in free convection laminar boundary layers. J. Fluid Mech. 30, 225239.Google Scholar
Priestley, C. H. B. & Ball, F. K. 1955 Continuous convection from an isolated source of heat. Q. J. R. Mel. Soc. 81, 144157.Google Scholar
Procaccia, I., Ching, E., Constantin, P., Kadanoff, L. P., Libchaber, A. & Wu, X. Z. 1991 Transitions in convective turbulence: the role of thermal plumes. Phys. Rev. A 44, 80918102.Google Scholar
Ranking, W. J. M. 1964 On plane water lines. Phil. Trans. R. Soc. Lond. A 154, 369391.Google Scholar
Schorr, A. W. & Gebhart, B. 1970 An experimental investigation of natural convection wake above a line heat source. Intl J. Heat Mass Transfer 13, 557571.Google Scholar
Shlien, D. J. 1976 Some laminar thermal and plume experiments. Phys. Fluids 19, 10891098.Google Scholar
Shlien, D. J. 1978 Transition of the axisymmetric starting plume cap. Phys. Fluids 21, 21542158.Google Scholar
Shlien, D. J. 1979 Relations between point sources buoyant convection phenomena. Phys. Fluids 22, 22772283.Google Scholar
Shlien, D. J. & Boxman, R. L. 1979 Temperature field measurement of an axisymmetric laminar plume. Phys. Fluids 22. 631634.Google Scholar
Shlien, D. J. & Boxman, R. L. 1981 Laminar starting plume temperature field measurement. Intl J. Heat Mass Transfer 24, 919930.Google Scholar
Shlien, D. J. & Brosh, A. 1979 Velocity field measurements of a laminar thermal. Phys. Fluids 22, 10441053.Google Scholar
Solomon, T. H. & Gollub, J. P. 1990 Sheared boundary layers in turbulent Rayleigh-Bénard convection. Phys. Rev. Lett. 64, 23822385.Google Scholar
Sparrow, E. M., Husar, R. B. & Goldstein, J. R. 1970 Observations and other characteristics of thermals. J. Fluid Mech. 41, 793806.Google Scholar
Taylor, G. I. 1941 British Rep. RC-210, June 27, 1941.
Taylor, G. I. 1950a The formation of a blast wave by a very intense explosion. I. Theoretical discussion. Proc. R. Soc. Lond. A 201, 159174.Google Scholar
Taylor, G. I. 1950b The formation of a blast wave by a very intense explosion. II. The atomic explosion of 1945. Proc. R. Soc. Lond. A 201, 175186.Google Scholar
Turner, J. S. 1962 The starting plume in neutral surroundings. J. Fluid Mech. 13, 356368.Google Scholar
Turner, J. S. 1969 Buoyant thermals and plumes. Ann. Rev. Fluid Mech. 1, 2944.Google Scholar
Turner, J. S. 1973 Buoyancy Effects in Fluids. Cambridge University Press.
Turner, J. S. 1986 Turbulent entrainment: the development of the entrainment assumption, and its application to geophysical flows. J. Fluid Mech. 173, 431471.Google Scholar
Vest, C. M. & Lawson, M. L. 1972 Onset of convection near a suddenly heated horizontal wire. Intl J. Heat Mass Transfer 15, 12811283.Google Scholar
Yih, C. S. 1951 Free convection due to a point source of heat. InProc. First US Natl Cong. Appl. Mech., pp. 941947.
Zeldovich, Ya. B. 1937 Limiting laws of freely rising convection currents. Zh. Eksp. Teor. Fiz. 7, 14631465.Google Scholar
Zocchi, G., Moses, E. & Libchaber, A. 1990 Coherent structures in turbulent convection, an experimental study. Physica A 166, 387407.Google Scholar
Zocchi, G., Tabeling, P. & Ben Amar, M. 1992 Saffman Taylor plumes. Phys. Rev. Lett. 69, 601604.Google Scholar
Zufiria, J. 1988 Bubble competition in Rayleigh Taylor instability. Phys. Fluids 31, 440446.Google Scholar