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The Calculation of Three-Dimensional Turbulent Boundary Layers. Part IV. Comparison with Measurements on the Rear of a Swept Wing

Published online by Cambridge University Press:  07 June 2016

N. A. Cumpsty
Affiliation:
Cambridge University Engineering Department
M. R. Head
Affiliation:
Cambridge University Engineering Department
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Summary

A boundary-layer development was measured on the near of a wing swept at 61°. The measurements approximately followed an external streamline from the minimum pressure to the neighbourhood of the separation line. Unfortunately the flow was found to be surprisingly sensitive to traverse gear interference. Moreover, the constraint imposed by the wind tunnel walls was sufficient to throw grave doubts on the use of the assumption of constant spanwise velocity to compute the external flow behaviour from the measured pressure distribution.

Comparison of the measurements with calculations using the method proposed by Cumpsty and Head showed the growth of streamwise momentum thickness, form parameter and crossflow to be seriously underestimated. However, only a small adjustment to the spanwise velocity outside the boundary layer over the rear of the wing was sufficient to bring the results into tolerable agreement. The necessity for such an adjustment to the spanwise velocity may be plausibly explained by the effect of tunnel constraints.

Type
Research Article
Copyright
Copyright © Royal Aeronautical Society. 1970

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References

1. Cumpsty, N. A. and Head, M. R. The calculation of three-dimensional turbulent boundary layers. Part I: Flow over the rear of an infinite swept wing. Aeronautical Quarterly, Vol. XVIII p. 55, February 1967.CrossRefGoogle Scholar
2. Smith, P. D. Calculation methods for three-dimensional turbulent boundary layers. ARC R & M 3523, 1966.Google Scholar
3. Cumpsty, N. A. and Head, M. R. The calculation of three-dimensional turbulent boundary layers. Part 4: Comparison of measurements with calculations on the rear of a swept wing. ARC Current Paper 1077, 1969.Google Scholar
4. Thompson, B. G. J. A new two-parameter family of mean velocity profiles for incompressible turbulent boundary layers on smooth walls. ARC R & M 3463, 1965.Google Scholar
5. Mager, A. Generalisation of the boundary-layer momentum integral equations to three-dimensional flows, including those of rotating systems. NACA Report 1067, 1952.Google Scholar