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On the secondary instability in inclined air layers

Published online by Cambridge University Press:  19 April 2006

Douglas W. Ruth
Affiliation:
Department of Mechanical Engineering, University of Waterloo, Ontario, Canada Present address: Department of Mechanical Engineering, University of Calgary, Alberta, Canada T2N 1N4.
G. D. Raithby
Affiliation:
Department of Mechanical Engineering, University of Waterloo, Ontario, Canada
K. G. T. Hollands
Affiliation:
Department of Mechanical Engineering, University of Waterloo, Ontario, Canada

Abstract

The heat transfer across an inclined air layer in the longitudinal roll regime often falls below expected values. A companion paper (Ruth et al. 1980) presents the heat transfer measurement and flow visualization observations; the present paper discusses the mechanisms which are thought to be responsible for this anomalous behaviour and formulates a simple model which correlates the results of our previous study and that of Hart (1971). The observed suppression of heat transfer below values expected for pure longitudinal roll motion is explained in terms of a shear instability. A stabilizing mechansim, which would restore the longitudinal rolls at higher Rayleigh numbers, is described; the return of the heat transfer to expected levels at higher Rayleigh numbers is ascribed to this mechanism. Comparisons are made between the results of the present model and the analyses of Clever & Busse (1977).

Type
Research Article
Copyright
© 1980 Cambridge University Press

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References

Bradshaw, P. 1969 The analogy between streamline curvature and buoyancy in turbulent shear flow. J. Fluid Mech. 36, 177191.Google Scholar
Clever, R. M. 1973 Finite amplitude longitudinal convection rolls in an inclined layer. Trans. A.S.M.E. J. Heat Transfer 95, 407408.Google Scholar
Clever, R. M. & Busse, F. H. 1977 Instabilities of longitudinal convection rolls in an inclined layer. J. Fluid Mech. 81, 107127.Google Scholar
Hart, J. E. 1971 Transition to a wavy vortex regime in convective flow between inclined plates. J. Fluid Mech. 48, 265271.Google Scholar
Hollands, K. G. T., Unny, T. E., Raithby, G. D., & Konicek, L. 1976 Free convective heat transfer across inclined air layers. Trans. A.S.M.E. J. Heat Transfer 98, 189193.Google Scholar
Nakagawa, Y. 1960 Heat transport by convection. Phys. Fluids 3, 8286.Google Scholar
Ruth, D. W. 1977 On free convection by longitudinal rolls in inclined infinite air layers heated from below. Ph.D. Thesis, University of Waterloo.
Ruth, D. W., Hollands, K. G. T. & Raithby, G. D. 1980 On free convection experiments in inclined air layers heated from below. J. Fluid Mech. 96, 461479.Google Scholar
Stuart, J. T. 1958 On the non-linear mechanics of hydrodynamic stability. J. Fluid Mech. 4, 121.Google Scholar