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Blockage Effects on Two-dimensional Bluff Body Flow

Published online by Cambridge University Press:  07 June 2016

J E Fackrell
J E Fackrell*
Affiliation:
Imperial College; now at Central Electricity Generating Board, Marchwood, Hampshire
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Summary

The time mean flow past a two-dimensional bluff body in a wind-tunnel is modelled by an adaptation of the numerical free-streamline method of Bearman and Fackrell. Provided the base pressure and separation positions are specified in advance, the method allows the calculation of the flow field outside the wake and in particular of the pressures on the wetted surface of the body. Good agreement of the predicted pressures with experimental results is obtained for a flat plate, wedge and circular cylinder at various blockage ratios. In addition to predicting the confined flow, it is shown that a free-air base pressure can be simply deduced from the confined base pressure. With an assumption that the separation positions are unaffected by blockage, this allows the free-air flow field to be calculated. By using an analogy to Roshko’s Strouhal number, which has been found to be invariant under constraint, a free-air Strouhal number can also be deduced.

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Type
Research Article
Information
Aeronautical Quarterly , Volume 26 , Issue 4 , November 1975, pp. 243 - 253
Copyright
Copyright © Royal Aeronautical Society. 1975

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References

1 Bearman, P W Fackrell, J E Calculation of two-dimensional and axisymmetric bluff body potential flow. Imperial College Aeronautics Department Report 74-07, 1974. To be published in the Journal of Fluid Mechanics.Google Scholar
2 Glauert, H Wind tunnel interference on wings, bodies and airscrews. ARC R & M 1566, 1933.Google Scholar
3 Thorn, A Blockage corrections in a closed high speed tunnel. ARC R & M 2033, 1943.Google Scholar
4 Allen, H J Vincenti, W G Wall interference in a two-dimensional flow wind tunnel with consideration of the effect of compressibility. NACA Report 782, 1944.Google Scholar
5 Woods, L C Two-dimensional flow of a compressible fluid past given curved obstacles with infinite wakes. Proc. Roy. Soc. A, Vol 227, p 367, 1955.Google Scholar
6 Roshko, A A new hodograph for free-streamline theory. NACA TN 3168, 1954.Google Scholar
7 Wu, T Y A wake model for free-streamline theory. Journal of Fluid Mechanics, Vol 13, p 161, 1962.CrossRefGoogle Scholar
8 Parkinson, G V Jandali, T A wake source model for bluff body potential flow. Journal of Fluid Mechanics, Vol 40, p 577, 1970.CrossRefGoogle Scholar
9 Maskell, E C A theory of the blockage effects on bluff bodies and stalled wings in a closed windtunnel. ARC R & M 3400, 1963.Google Scholar
10 Ai, K I The wall effect in cavity flows. Transactions ASME, Journal of Basic Engineering, Vol 88, p 132, 1966.CrossRefGoogle Scholar
11 Modi, V J Sherbiny, S El On the wall confinement effects in the industrial aerodynamic studies. Paper No. 116 at the Symposium on Vibration Problems in Industry, Keswick, England, 1973.Google Scholar
12 Fage, A Johansen, F C On the flow of air behind an inclined flat plate of infinite span. ARC R & M 1104, 1927.Google Scholar
13 Ramamurthy, A S Lee, P M Wall effects on flow past bluff bodies. Journal of Sound and Vibration, Vol 31, p 443, 1973.CrossRefGoogle Scholar
14 Abernathy, F H Flow over an inclined flat plate. Transactions ASME, Journal of Basic Engineering, Vol 84, p 380, 1962.CrossRefGoogle Scholar
15 Raju, K G Ranga Garde, R J Resistance of an inclined plate placed on a plane boundary in two-dimensional flow. Transactions ASME, Journal of Basic Engineering, Vol 92, p 21, 1970.CrossRefGoogle Scholar
16 Arie, M Rouse, H Experiments on two-dimensional flow over a normal wall. Journal of Fluid Mechanics, Vol 1, p 129, 1956.CrossRefGoogle Scholar
17 Fage, A Falkner, V M Further experiments on the flow around a circular cylinder. ARC R & M 1369, 1931.Google Scholar
18 Roshko, A On the drag and shedding frequency of two-dimensional bluff bodies. NACA TN 3169, 1954.Google Scholar