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Equilibrium and near-equilibrium turbulent boundary layers

Published online by Cambridge University Press:  29 March 2006

M. R. Head
M. R. Head
Affiliation:
Engineering Department, University of Cambridge
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Abstract

A well-tested integral method has been used to calculate turbulent boundary-layer development for the distribution of external velocity given by U ∝ x−0.255. The results suggest that different values of the initial momentum thickness, so long as this is below some critical value, produce a range of equilibrium layers having widely different values of the form parameter G. For values of the initial momentum thickness greater than the critical value, layers are produced which proceed more or less rapidly to separation. These results provide a plausible explanation for conflicting experimental observations made in the past.

Additional calculations for the flows U ∝ x−0.15 and U ∝ x−0.35 suggest that, in the first case, a unique equilibrium condition is approached whatever the initial momentum thickness unless this exceeds some critical value; in the second case no equilibrium condition appears possible.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 73 , Issue 1 , 13 January 1976 , pp. 1 - 8
Copyright
© 1976 Cambridge University Press

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