Hostname: page-component-78c5997874-g7gxr Total loading time: 0 Render date: 2024-11-05T08:55:15.379Z Has data issue: false hasContentIssue false

The assessment of boundary layer two-dimensionality

Published online by Cambridge University Press:  04 July 2016

C. J. Fraser*
Affiliation:
Department of Mechanical and Industrial Engineering, Dundee College of Technology

Summary

The results of an experimental evaluation of three assessment criteria for boundary layer two-dimensionality are presented. The criteria include the so-called ‘two pin test', the momentum balance principle and the cross-stream variation in local skin friction coefficient. Extensive spanwise measurements in the flows investigated highlight the relative merits and limitations of the criteria imposed.

The momentum balance method is found to be the most informative technique, with the proviso that the test data must be interpreted with some care if measurements are restricted along a single streamwise axis.

The two pin test is found to provide a worthwhile complimentary addition to momentum balance data, whereas the spanwise variation in local skin friction coefficient is less conclusive as regards flow two-dimensionality.

Excepting the case of adverse pressure gradient flows, the momentum balance equation is seen as a viable experimental means of estimating the local skin friction coefficient in boundary layers where measurement is problematical, as in the case of transitional boundary layers. In such cases, the two pin test could be used as the sole means of confirming the flow two-dimensionality.

Type
Research Article
Copyright
Copyright © Royal Aeronautical Society 1986 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1. Coles, D. E. and Hirst, E. A. Computation of turbulent boundary layers. AFOSR-IFP, Proc Stanford Conference, 1968.Google Scholar
2. Preston, J. H. The determination of turbulent skin friction by means of Pitot tubes. J Roy Aero Soc, 1954, 58.Google Scholar
3. Patel, V. C. Calibration of the Preston tube and limitations on its use in pressure gradients. J Fluid Mech, 1965, 23, part 1.Google Scholar
4. Fraser, C. J. and Milne, J. S. Boundary layer development from transition provoking devices. I J Heat & Fluid Flow, 1980, 2, No 4.Google Scholar
5. Hall, D. J. Boundary layer transition. PhD thesis, Liverpool University, 1968.Google Scholar
6. Tani, I., Komoda, H., Komatsu, Y. and Iuchi, M. Boundary layer transition by isolated roughness. Aero Res Inst, Univ of Tokyo, 1962, Rept No 375, 28, No 7.Google Scholar
7. Potter, J. L. Subsonic boundary layer transition caused by single roughness elements. J Aero Sc, 1957, 24, No 2.Google Scholar
8. Murlis, J. The structure of turbulent boundary layers at low Reynolds numbers. PhD thesis, Imp Coll, London 1975.Google Scholar
9. Winter, K. G. An outline of the techniques available for the measurement of skin friction in turbulent boundary layers. RAE, Tech Memo, AERO 1656, 1975.Google Scholar
10. Arnal, D., Juillen, J. C. and Michel, R. Analyse experimentale et calcul de l'apparition et du la developpment de la transition de la couche limite. Paper 13, Proc AGARD Laminar-turbulent transition symposium, Copenhagen, AGARD-CP-224, 1977.Google Scholar
11. Dhawan, S. and Narasimha, R. Some properties of boundary layer flow during the transition from laminar to turbulent motion. J Fluid Mech, 1958, 3.Google Scholar
12. Thwaites, B. Approximate calculation of the laminar boundary layer. Aero Quart, 1949, 1.Google Scholar
13. Ludweig, H. and Tillman, W. Investigation of the wall shearing stress in turbulent boundary layers. NACA, Tech Memo, 1950, 1285.Google Scholar
14. East, L. F. Spatial variations of the boundary layer of a large low speed wind tunnel. Aero J, 1972, 76.Google Scholar
15. Prahlad, T. S. Yaw characteristics of Preston tubes. AIAA, Tech Note, 1972, 10, No 3.Google Scholar
16. Rajaratnam, N. and Muralidhar, D. Yaw probe used as a Preston tube, AIAA, Tech Note. 1968, 72.Google Scholar
17. Johnston, J. P. On the three-dimensional turbulent boundary layer generated by secondary flow. J. Bas Eng, Trans ASME, series D. 1960, 82.Google Scholar
18. Green, J. E., Weeks, D.J. and Brooman, J.W.F. Prediction of turbulent boundary layers and wakes in compressible flow by a lag-entrainment method. Aero Res Court, 1977, R&M No 3791.Google Scholar
19. Clauser, F. Turbulent boundary layers in adverse pressure gradients. J Aero Sc, 1954, 21.Google Scholar
20. Huffman, G. D. and Bradshaw, P. A note on von Karman's constant in low Reynolds number turbulent flows. J Fluid Mech, 1972, 53, Part 1.Google Scholar
21. Murlis, J., Tsai, H. M. and Bradshaw, P. The structure of turbulent boundary layers at low Reynolds numbers. J Fluid Mech, 1982, 122.Google Scholar
22. Rotta, J. C. Turbulent boundary layers in incompressible flow. Prog Aero Sc, 1962, 2, 1219.Google Scholar