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An Experimental Investigation of the Wake of an Axisymmetric Body with a Slanted Base

Published online by Cambridge University Press:  07 June 2016

X.J. Xia  and
P.W. Bearman
X.J. Xia
Affiliation:
Department of Aeronautics, Imperial College, London, S.W.7.
P.W. Bearman
Affiliation:
Department of Aeronautics, Imperial College, London, S.W.7.
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Summary

The effect of base slant on the base pressure distribution, drag coefficient and vortex shedding characteristics of a model consisting of an axisymmetric main body with an ellipsoidal nose have been investigated for three fineness ratios; 3, 6 and 9. A sudden change in the drag coefficient and separated flow pattern is observed at a critical slant angle (for constant incidence) or at a critical angle of incidence (for a constant base slant angle). The tests confirm that the value of the maximum drag coefficient is extremely sensitive to angle of incidence. Measurements of the frequency of vortex shedding are presented and the structure of the wake is investigated using smoke visualization and hot-wire correlation measurements. The wake is found to be far less stable than that from a two-dimensional bluff body and the vortex structures are sometimes in-phase and sometimes out of phase across the wake. The effect of free-stream turbulence on this family of body shapes is observed to be different to that on three-dimensional blunt-faced bluff bodies. Free-stream turbulence is found to have a minimal effect on base pressure for slant angles giving a recirculating type near wake flow. When longitudinal vortices are present the addition of free-stream turbulence slightly reduces the magnitude of the peak suctions recorded on the base but has little effect on base drag.

Type
Research Article
Information
Aeronautical Quarterly , Volume 34 , Issue 1 , February 1983 , pp. 24 - 45
Copyright
Copyright © Royal Aeronautical Society. 1983

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References

1 Achenbach, E. Vortex shedding from spheres. J. Fluid Meah., Vol. 62, pp 209-221, 1974 Google Scholar
2 Bearman, P.W. Bluff body flows applicable to vehicle aerodynamics. A.S.M.E. J. Fluid Eng., Vol. 102, pp 265-274, 1980 CrossRefGoogle Scholar
3 Bearman, P.W. An investigation on the forces on flat plates in turbulent flow. NPL Aero Report 1296, 1969 Google Scholar
4 Calvert, J.R. Experiments on the low-speed flow past cones. J. Fluid Meah., Vol. 27, pp 273-289, 1967 Google Scholar
5 Davies, M.E. Wakes of oscillating bluff bodies. Ph.D. Thesis, Department of Aeronautics, Imperial College, University of London, 1975 Google Scholar
6 Fuchs, H.V., Mercker, E. and Michel, U. Large-scale coherent structures in the wake of axisymmetric bodies. J. Fluid Meah., Vol. 93, Part 1, pp 185-207, 1979 CrossRefGoogle Scholar
7 Hoare, G.T. Pressure measurements on upswept afterbodies. Undergraduate project, Department of Aeronautics, Imperial College, 1978 Google Scholar
8 Humphries, W. and Vincent, J.H. Experiments to investigate transport processes in the near wakes of disks in turbulent air flow. J. Fluid Meah., Vol. 75, pp 737-749, 1976 CrossRefGoogle Scholar
9 Janssen, L.J. and Hucho, W.H. Aerodynamische formoptimierung der type VW-Golf and VW-Scirocco. Kolloquium ueber Industrie-Aerodynamik, Aachen, part 3, pp 46-49, 1974 Google Scholar
10 Martin, L.J. The effect of turbulence on the flow around a cube. M.Sc. Dissertation, Department of Aeronautics, Imperial College, 1977 Google Scholar
11 Maull, D.J. The drag of slant-based bodies of revolution. The Aeronautical Journal, Vol. 84, pp 164-166, 1980 CrossRefGoogle Scholar
12 Morel, T. The effect of base slant on the flow pattern and drag of three-dimensional bodies with blunt ends. Aerodynamic Drag Mechanisms of Bluff Bodies and Road Vehicles, General Motors Research Laboratories Symposium, 1976 Google Scholar
13 Morel, T. Effect of base slant on flow in the near wake of an axisymmetric cylinder. Aero. Quart., Vol. 31, pp 132-150, 1980 Google Scholar
14 Peake, D.J. Controlled and uncontrolled flow separation in three-dimensions. National Research Council Canada. Aero. Rep. LR-591, 1976 Google Scholar
15 Perry, A.E. and Lim, T.T. Coherent structure in coflowing jets and wakes. J. Fluid Mech, Vol. 88, pp 451-464 Google Scholar
16 Roberts, J.B. Coherence measurements in an axisymmetric wake. AIAA, Vol. 11, pp 1569-1571, 1973 CrossRefGoogle Scholar
17 Stuart, A.D. and Jones, A.T. The drag of an upswept rear fuselage. Undergraduate project, Department of Aeronautics, Imperial College, 1977 Google Scholar