Hostname: page-component-cd9895bd7-jn8rn Total loading time: 0 Render date: 2024-12-27T13:02:17.133Z Has data issue: false hasContentIssue false
  • English
  • Français

Sting-free measurements of sphere drag in laminar flow

Published online by Cambridge University Press:  29 March 2006

M. Vlajinac  and
E. E. Covert
M. Vlajinac
Affiliation:
Aerophysics Laboratory, Massachusetts Institute of Technology
E. E. Covert
Affiliation:
Aerophysics Laboratory, Massachusetts Institute of Technology
Get access Rights & Permissions [Opens in a new window]

Abstract

An aerodynamic investigation was conducted to determine the laminar-flow drag coefficient of spheres of various sizes in a subsonic wind tunnel. The tests were conducted using the M.I.T.-N.A.S.A. prototype magnetic-balance system. By measuring the drag of different sized spheres without model support interference the tunnel wall effect can be deduced. The present results indicate that the classical wind tunnel correction does not completely account for the effects of model size and wall interference. That is, the corrected drag coefficient data for the different sphere sizes differ among themselves in the region of Reynolds number overlap.

A comparison of the present sphere drag results with those of numerous other investigations including free-flight and ballistic-range data is given. The drag coefficients presented here are slightly lower than those of other workers for Reynolds numbers ranging from 20 000 to 150 000, but fall between the limits of experimental scatter for Reynolds numbers from 150 000 to 260 000.

An analysis of the estimated error in the present data indicates the primary source to be measurement of the wind tunnel parameters rather than errors resulting from the balance system.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 54 , Issue 3 , 8 August 1972 , pp. 385 - 392
Copyright
© 1972 Cambridge University Press

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

Bailey, A. B. & Hiatt, J. 1971 Free-flight measurements of sphere drag at subsonic, transonic, supersonic and hypersonic speeds for continuum, transition and near-free-molecule flow conditions. A.E.D.C. Tech. Rep. 70–291.Google Scholar
Bozorth, R. M. 1952 Ferromagnetism. Von Nostrand.
Gilliam, G. D. 1969 Data reduction techniques for use with a wind tunnel magnetic suspension system. N.A.S.A. Current Rep. no. 111844.Google Scholar
Goin, K. L. & Lawrence, W. R. 1968 Subsonic drag of spheres at Reynolds numbers from 200 to 10000 A.I.A.A.J. 6, 961.Google Scholar
Hoerner, S. 1935 Tests of spheres with reference to Reynolds number, turbulence and surface roughness. N.A.C.A. Tech. Mem. no. 777.Google Scholar
Hoerner, S. 1965 Fluid-Dynamic Drag, 2nd edn. Published by the author, Midland Park, N.J.
Judd, M., Vlajinac, M. & Covert, E. E. 1971 Sting-free drag measurements on ellipsoidal cylinders at transition Reynolds numbers J. Fluid Mech. 48, 353.Google Scholar
Millikan, C. B. & Klein, A. L. 1933 The effect of turbulence: an investigation of maximum lift coefficient and turbulence in wind tunnels and in flight. Aircr. Engng. p. 196.Google Scholar
Pankhubst, R. C. & Holder, D. W. 1952 Wind Tunnel Technique. London: Pitman.
Roos, F. W. & Willmarth, W. W. 1971 Some experimental results on sphere and disk drag A.I.A.A. J. 9, 285.Google Scholar
Stephens, T. 1969 Design, construction and evaluation of a magnetic suspension and balance system for wind tunnels. N.A.S.A. Langley Contractor Rep. CR-66903.Google Scholar