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Calculation of a Turbulent Boundary Layer Downstream of a Small Step Change in Surface Roughness

Published online by Cambridge University Press:  07 June 2016

R A Antonia
Affiliation:
Department of Mechanical Engineering, The University of Sydney
D H Wood
Affiliation:
Department of Mechanical Engineering, The University of Sydney
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Summary

Measurements of mean velocity and Reynolds shear stress have been made in a turbulent boundary layer downstream of a small step change in surface roughness. Upstream of the step the surface is smooth, while downstream it consists of a d-type rough wall made up by a series of two-dimensional elements of square cross section placed transversely across the flow and spaced one element width apart in the direction of the flow. The calculated mean velocity and Reynolds shear stress profiles obtained using the method of Bradshaw, Ferriss and Atwell are in good agreement with the measurements throughout the relaxation region of the layer. Well downstream the calculation method adequately reproduces the self-preserving features of a d-type rough wall.

Type
Research Article
Copyright
Copyright © Royal Aeronautical Society. 1975

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