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Stability of vertical natural convection boundary layers: some numerical solutions

Published online by Cambridge University Press:  29 March 2006

C. A. Hieber
Affiliation:
Department of Thermal Engineering, Cornell University Clarkson College of Technology, Potsdam, New York.
B. Gebhart
Affiliation:
Department of Thermal Engineering, Cornell University

Abstract

Linear stability theory is applied to the natural convection boundary layer arising from a vertical plate dissipating a uniform heat flux. By using a numerical procedure which is much simpler than those previously employed on this problem, computer solutions are obtained for a much larger range of the Grashof number (G). For a Prandtl number (σ) of 0·733, it is found that, as G → ∞: the effect of temperature coupling vanishes more rapidly than that of viscosity; the upper branch of the neutral curve is oscillatory but does approach a finite non-zero inviscid asymptote. For moderate and large values of σ, a loop appears in the neutral stability curve as a result of the merging of two unstable modes. As σ → ∞, the mode associated with the uncoupled (i.e. Orr–Sommerfeld) problem rapidly becomes less unstable than that arising from the temperature coupling, with the stability characteristics being independent of the thermal capacity of the plate. For small values of σ, only one unstable mode is found to exist with the coupling effect being negligible in the case of large thermal capacity plates but markedly destabilizing when the thermal capacity is small.

By obtaining numerical results out to G ≈ 1010 for the cases σ = 0·733 and 6·7, it becomes possible to attempt to directly relate the theory to the actual observance of turbulent transition. Based upon comparison with available experimental data, empirical correlations are obtained between the linear stability theory and the régimes in which: (i) the boundary layer is first noticeably oscillatory; (ii) the mean (temporal) flow quantities first deviate significantly from those of laminar flow.

Type
Research Article
Copyright
© 1971 Cambridge University Press

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References

Betchov, R. & Criminale, W. O. 1967 Stability of Parallel Flows. Academic.
Cheesewright, R. 1968 Turbulent natural convection from a vertical plane surface J. Heat Transfer, 90, 18.Google Scholar
Colak-Antic, P. 1964 Hitzdrahtmessungen des Laminar-Turbulenten Umschlags bei freier Konvektion. Jahrbuch 1964 der Wissenschaftlichen Gesellschaft fur Luft-und-Raumfahrt E. V. pp. 172176.
Drazin, P. G. & Howard, L. N. 1962 The instability to long waves of unbounded parallel inviscid flow J. Fluid Mech. 14, 257283.Google Scholar
Dring, R. P. & Gebhart, B. 1968 A theoretical investigation of disturbance amplification in external laminar natural convection J. Fluid Mech. 34, 541564.Google Scholar
Dring, R. P. & Gebhart, B. 1969 An experimental investigation of disturbance amplification in external natural convection flow J. Fluid Mech. 36, 447464.Google Scholar
Eckert, E. R. G. & Soehngen, E. 1951 Interferometric studies on the stability and transition to turbulence of a free convection boundary layer. Proceedings of the General Discussion on Heat Transfer, London, pp. 321323. (Published by A.S.M.E.).
Eckert, E. R. G., Hartnett, J. P. & Irvine, T. F. 1960 Flow visualization studies of transition to turbulence in free-convection flow. A.S.M.E. Paper no. 60-WA-250.Google Scholar
Gebhart, B. 1969 Natural convection flow, instability, and transition J. Heat Transfer, 91, 293309.Google Scholar
Gill, A. E. & Davey, A. 1969 Instabilities of a buoyancy-driven system J. Fluid Mech. 35, 775798.Google Scholar
Hieber, C. A. & Gebhart, B. 1971 Stability of vertical natural convection boundary layers: expansions at large Prandtl number. To appear in J. Fluid Mech.Google Scholar
Kaplan, R. E. 1964 The stability of laminar incompressible boundary layers in the presence of compliant boundaries. Mass. Inst. Tech., Aeroelastic & Structures Research Lab. TR 116-1.Google Scholar
Knowles, C. P. & Gebhart, B. 1968 The stability of the laminar natural convection boundary layer J. Fluid Mech. 34, 657686.Google Scholar
Knowles, C. P. & Gebhart, B. 1969 An experimental investigation of the stability of laminar natural convection boundary layers. Progress in Heat and Mass Transfer, vol. 2. Pergamon.
Kurtz, E. F. & Crandall, S. H. 1962 Computer-aided analysis of hydrodynamic stability J. Math. Phys. 41, 264297.Google Scholar
Mack, L. M. 1965 Computation of the stability of the laminar compressible boundary layer. Methods in Computational Physics, vol. 4. Academic.
Morawetz, C. S. 1952 The eigenvalues of some stability problems involving viscosity J. Rat. Mech. Anal. 1, 579603.Google Scholar
Nachtsheim, P. R. 1963 Stability of free-convection boundary layer flows. NASA TN D-2089.Google Scholar
Ostrach, S. 1964 Laminar flows with body forces. In Theory of Laminar Flows (ed. F. K. Moore). Princeton University Press.
Ostrach, S. Maslen, S, H. 1961 Stability of laminar viscous flows with a body force. Int. Heat Transfer Conf., University of Colorado, 10171023. (Published by A.S.M.E.).
Plapp, J. E. 1957 Laminar boundary layer stability in free convection. Ph.D. Thesis, Calif. Instit. Tech.
Polymeropoulos, C. E. 1966 A study of the stability of free convection flow over a uniform flux plate in nitrogen. Ph.D. Thesis, Cornell University.
Polymeropoulos, C. E. & Gebhart, B. 1967 Incipient instability in free convection laminar boundary layers J. Fluid Mech. 30, 225239.Google Scholar
Smith, A. M. O. 1957 Transition pressure gradient and stability theory Proc. 9th Int. Congress of Appl. Mech., Brussels, 4, 234244.Google Scholar
Sparrow, E. M. & Gregg, J. L. 1956 Laminar free convection from a vertical plate with uniform surface heat flux Trans. A.S.M.E. 78, 435440.Google Scholar
Sparrow, E. M., Tsou, F. K. & Kurtz, E. F. 1965 Stability of laminar free convection flow on a vertical plate Phys. Fluids, 8, 15591561.Google Scholar
Szewczyk, A. A. 1962 Stability and transition of the free-convection layer along a vertical flat plate Int. J. Heat Mass Transfer, 5, 903914.Google Scholar
Vliet, G. C. & Liu, C. K. 1969 An experimental study of turbulent natural convection boundary layers J. Heat Transfer, 91, 517531.Google Scholar