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The Critical Height of Distributed Roughness to Cause Boundary Layer Transition

Published online by Cambridge University Press:  04 July 2016

R. L. Dommett*
Affiliation:
Royal Aircraft Establishment, Farnborough

Extract

It has been found that there is a critical height for “sandpaper” type roughness below which no measurable disturbances are introduced into a laminar boundary layer and above which transition is initiated at the roughness. Braslow and Knox have proposed a method of predicting this height, for flow over a flat plate or a cone, using exact solutions of the laminar boundary layer equations combined with a correlation of experimental results in terms of a Reynolds number based on roughness height, k, and local conditions at the top of the elements. A simpler, yet more general, method can be constructed by taking additional advantage of the linearity of the velocity profile near the wall in a laminar boundary layer.

Type
Technical Notes
Copyright
Copyright © Royal Aeronautical Society 1959

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References

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