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Stability and transition of buoyancy-induced flows in a stratified medium

Published online by Cambridge University Press:  29 March 2006

Yogesh Jaluria
Affiliation:
Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, New York 14850 Present address: Engineering Research Center, Western Electric Co., Inc., P.O. Box 900, Princeton, New Jersey 08540, U.S.A.
Benjamin Gebhart
Affiliation:
Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, New York 14850

Abstract

An experimental and theoretical investigation has been carried out to determine the effect of a stable ambient thermal stratification on the developing buoyancyinduced flow adjacent to a flat vertical surface dissipating a uniform heat flux. The nature of the resulting base flow and its instability characteristics, linearized for two-dimensional disturbances, were analysed for Prandtl numbers Pr of 6·7 and 0·733, for several levels of ambient stratification. Stratification was found to cause initial stabilization of the flow but later destabilization downstream. Disturbance growth rates, frequency filtering and amplitude distributions across the boundary region were calculated. These aspects of the disturbance field were measured in a flow generated by an electrically heated metal foil, with artificially introduced two-dimensional disturbances, in water (Pr = 6–7). The experimental results are in very good agreement with the calculations. Measurements of natural transition indicate that a stable ambient stratification delays the onset of transition. A tentative transition-correlating parameter is generalized to include the effect of stratification.

Type
Research Article
Copyright
© 1974 Cambridge University Press

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References

Birikh, R. V., Gershuni, G. Z., Zhukhovitski, E. M. & Rudakov, R. N. 1969 Stability of the steady convective motion of a fluid with a longitudinal temperature gradient Prikl. Math. Mech. 33, 958.Google Scholar
Cheesewright, R. 1967 Natural convection from a plane, vertical surface in nonisothermal surroundings Int. J. Heat Mass Transfer, 10, 1847.Google Scholar
Dring, R. P. 1968 A theoretical and experimental investigation of disturbance amplification in external laminar natural convection. Ph.D. thesis, Cornell University.
Dring, R. P. & Gebhart, B. 1968 A theoretical investigation of disturbance amplification in external natural convection J. Fluid Mech. 34, 551.Google Scholar
Eichhorn, R. 1969 Natural convection in a thermally stratified fluid Prog. Heat Mass Transfer, 2, 41.Google Scholar
Gebhart, B. 1971 Heat Transfer, 2nd ed. McGraw-Hill.
Gebhart, B. 1973 Natural convection flows and stability Adv. in Heat Transfer, 9, 273.Google Scholar
Gill, A. E. 1966 The boundary-layer regime for convection in a rectangular cavity J. Fluid Mech. 26, 515.Google Scholar
Gill, A. E. & Davey, A. 1969 Instabilities of a buoyancy-driven system J. Fluid Mech. 35, 775.Google Scholar
Godaux, F. & Gebhart, B. 1974 An experimental study of the transition of natural convection flow adjacent to a vertical surface Int. J. Heat Mass Transfer, 17, 93.Google Scholar
Hart, J. E. 1971 Stability of the flow in a differentially heated inclined box J. Fluid Mech. 47, 547.Google Scholar
Hieber, C. A. & Gebhart, B. 1971 Stability of vertical natural convection boundary layers: some numerical solutions. J. Fluid Mech. 48, 625.Google Scholar
Iyer, P. A. 1973 Instabilities in buoyancy-driven boundary-layer flows in a stably stratified medium Boundary-Layer Met. 5, 53.Google Scholar
Jaluria, Y. 1974 A study of stability, transition and separation in natural convection flows. Ph.D. thesis, Cornell University.
Jaluria, Y. & Gebhart, B. 1973 An experimental study of nonlinear disturbance behaviour in natural convection J. Fluid Mech. 61, 337.Google Scholar
Jaluria, Y. & Gebhart, B. 1974 On transition mechanisms in vertical natural convection flow J. Fluid Mech. 66, 309.Google Scholar
Klebanoff, P. S., Tidstrom, K. D. & Sargent, L. M. 1962 The three-dimensional nature of boundary-layer instability J. Fluid Mech. 12, 1.Google Scholar
Knowles, C. P. & Gebhart, B. 1968 The stability of the laminar natural convection boundary layer J. Fluid Mech. 34, 657.Google Scholar
Prandtl, L. 1952 Essentials of Fluid Dynamics, p. 422. New York: Hafner.
Yang, K. T., Novotny, J. L. & Cheng, Y. S. 1972 Laminar free convection from a non-isothermal plate immersed in a temperature stratified medium Int. J. Heat Mass Transfer, 15, 1097.Google Scholar