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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

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