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The Effect of Base Bleed on the Flow behind a Two-Dimensional Model with a Blunt Trailing Edge

Published online by Cambridge University Press:  07 June 2016

P. W. Bearman*
Affiliation:
Cambridge University Engineering Laboratory*
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Summary

The effects of base bleed on the flow about a two-dimensional model with a blunt trailing edge were examined at Reynolds numbers, based on model base height, between 1·3×104 and 4·1×104. The ratio of boundary layer thickness at the trailing edge to half the model base height was approximately 0·4. Measurements were made of base pressure, vortex shedding frequency and the distance to vortex formation. With a sufficiently large bleed quantity the regular vortex street pattern disappeared and the base drag of the section was reduced to about a third of its value without bleed. The base pressure was found to vary linearly with the inverse of the vortex formation distance. Results of a previous splitter plate investigation were found to agree closely with those of the present experiments.

Type
Research Article
Copyright
Copyright © Royal Aeronautical Society. 1967

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References

1. Chapman, D. R. Reduction of profile drag at supersonic velocities by the use of airfoil sections having a blunt trailing edge. NACA TN 3503, 1955.Google Scholar
2. Holder, D. W. The transonic flow past two-dimensional aerofoils. Journal of the Royal Aeronautical Society, Vol. 68 p. 501, August 1964.CrossRefGoogle Scholar
3. Nash, J. F. A review of research on two-dimensional base flow. ARC R & M 3323, 1962.Google Scholar
4. Bearman, P. W. Investigation of the flow behind a two-dimensional model with a blunt-trailing-edge and fitted with splitter plates. Journal of Fluid Mechanics, Vol. 21, Part 2 p. 241, 1965.Google Scholar
5. Wood, C. J. The effect of base bleed on a periodic wake. Journal of the Royal Aeronautical Society, Vol. 68 p. 477, July 1964.Google Scholar
6. Maskell, E. C. A theory of the blockage effects on bluff bodies and stalled wings in a closed wind tunnel. ARC R & M 3400, 1965.Google Scholar
7. Nash, J. F. An approximate method for the prediction of the zero-lift pressure distribution and drag of symmetrical blunt-trailing-edge aerofoil sections at subsonic speeds, in the absence of a vortex street. ARC Report 26 117, 1964.Google Scholar
8. Nash, J. F., Quincey, V. G. and Caixinan, J. Experiments on two-dimensional base flow at subsonic and transonic speeds. ARC Report 25 070, 1963.Google Scholar
9. Bearman, P. W. A study of unsteady base flows. PhD Thesis, University of Cambridge, 1965.Google Scholar
10. Abernathy, F. H. and Kronauer, R. E. The formation of vortex streets. Journal of Fluid Mechanics, Vol. 13, Part 1 p. 1, 1962.Google Scholar
11. Pankhurst, R. C. and Holder, D. W. Wind tunnel technique (1st Edition reprinted). Pitman, London, 1965.Google Scholar