Hostname: page-component-848d4c4894-v5vhk Total loading time: 0 Render date: 2024-07-07T06:16:26.737Z Has data issue: false hasContentIssue false
  • English
  • Français

The Unsteady Lift on Bluff Cylindrical Bodies in Unsteady Flow

Published online by Cambridge University Press:  07 June 2016

H. Stapountzis  and
J.M.R. Graham
H. Stapountzis
Affiliation:
Department of Aeronautics, Imperial College of Science and Technology, London
J.M.R. Graham
Affiliation:
Department of Aeronautics, Imperial College of Science and Technology, London
Get access

Summary

The unsteady lift generated on a NACA 0015 aerofoil, a D cylinder (with the flat face down-stream) and an elliptic cylinder was measured when these bodies were exposed to a flow with a two-dimensional sinusoidal upwash at reduced frequencies 0.05 to 0.8. The mean flow Reynolds numbers were in the range 1.2 × 105 to 3 × 105. Unsteady thin aerofoil theory was used in an attempt to predict the unsteady lift on the bluff bodies, as well as the aerofoil section for fequencies in the low range below the vortex shedding frequency. The results were quite accurate for the aerofoil and the D cylinder, but the aerodynamic admittance predicted by this theory for the elliptic cylinder was significantly above that measured experimentally. The movement of the two free separation points was found to play an important role in the characteristic lift behaviour of the elliptic cylinder.

Type
Research Article
Information
Aeronautical Quarterly , Volume 33 , Issue 3 , August 1982 , pp. 219 - 236
Copyright
Copyright © Royal Aeronautical Society. 1982

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 Davenport, A.G. An application of statistical concepts to the wind loading of structures. Proc. Inst. Civil Eng. 6480, Vol. 19, 1961 Google Scholar
2 Graham, J.M.R. Lift forces on cylinders in a turbulent flow. Int. Symp. vibration problems in industry, Keswick, UK, 1973 Google Scholar
3 Moore, F.K. Lift hysteresis at stall as an unsteady boundary layer phenomenon. NACA TN 3571, 1955 Google Scholar
4 Sears, W.R. Unsteady motion of aerofoils with boundary layer separation. AIAA Journal, Vol. 14, 1976 Google Scholar
5 Giesing, J.P. Non-linear two-dimensional unsteady potential flow with lift. Journal of Aircraft, Vol. 5, 1968 Google Scholar
6 Clements, R. and Maull, D.J. The representation of sheets of vorticity by discrete vortices. Progr. in Aerosp. Sci., Vol. 16, 1976 Google Scholar
7 Sears, W.R. Some aspects of non-stationary aerofoil theory and its practical application. Jour. Aero. Soi., Vol. 16, 1941 Google Scholar
8 Stapountzis, H. Lift forces on cylindrical bodies in unsteady flows. Ph.D. thesis, London University I.C., 1978 Google Scholar
9 Davies, M.E. Spectral analysis programs POWSPEC and COPHASE, I.C. Aero TN74-103, 1974 Google Scholar
10 Allen, H.J. and Vincenti, W.G. Wall interference in a two-dimensional flow wind tunnel, with consideration of the effect of compressibility. NACA Rep. 782, 1944 Google Scholar
11 Maskell, E.C. A theory of the blockage effects on bluff bodies and stalled wings in a closed wind tunnel. ARC R & M 3400, 1963 Google Scholar
12 Bechert, D. and Pfizenmaier, E. Optical compensation measurements on the unsteady exit condition at a nozzle discharge edge. Jour. Fluid Mech., Vol. 71, 1975 Google Scholar
13 Fleeter, S. Trailing edge conditions for unsteady flows at high reduced frequency. 17th AIAA Aerosp. Sci. Meeting, paper 79-0152, 1979 Google Scholar
14 Maeda, H. and Kobayakawa, M. Studies on the gust response of a wing. I: Response of a two dimensional rigid wing. Memoirs Kyoto University, Vol. 32, 1970 Google Scholar