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Blockage Corrections for Blunt-Based Bodies of Revolution

Published online by Cambridge University Press:  04 July 2016

W. A. Mair*
Affiliation:
Engineering Department, Cambridge University

Extract

Calvert has considered alternative methods of estimating the blockage corrections for blunt-based bodies of revolution in closed wind tunnels at low Mach numbers. His models were all of maximum diameter 152 mm, with an ellipsoidal nose section 203 mm long followed by a cylindrical afterbody. The ratio of overall length L to maximum diameter d varied from about 1.5 to 5.5. For each model the base pressure was measured in wind tunnels of two different sizes, so that the blockage correction factor e for the smaller tunnel could be derived for each model from the experimental results. These experimental values of e were compared with alternative theoretical estimates, using the methods given by Evans, Maskell and Pank-hurst and Holder.

Type
Technical Notes
Copyright
Copyright © Royal Aeronautical Society 1968 

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References

1. Calvert, J. R. Blockage corrections for blunt-based bodies of revolution. J Roy Aero Soc, Vol 70, pp 532533, April 1966.Google Scholar
2. Evans, J. Y. G. Corrections to velocity for wall constraint in any 10x7 rectangular subsonic wind tunnel. ARC R and M 2662, 1953.Google Scholar
3. Maskell, E. C. A theory of the blockage effects on bluff bodies and stalled wings in a closed wind tunnel. ARC R and M 3400, 1965.Google Scholar
4. Pankhurst, R. C. and Holder, D. W. Wind-Tunnel Technique, pp 340348. Pitman, 1952.Google Scholar