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The pressure distribution around unsteady boundary layers

Published online by Cambridge University Press:  26 April 2006

Yang-Moon Koh
Yang-Moon Koh
Affiliation:
Department of Mechanical Engineering, University of Ulsan, Ulsan 680-749, South Korea
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Abstract

The effect of an unsteady boundary layer on the pressure field around a bluff body has been investigated. It is found that in an unsteady flow the friction drag is always accompanied by a form drag whose magnitude is comparable with that of the former, and thus the pressure field around the unsteady boundary layer can be very different from that of an inviscid irrotational flow. The definition of the displacement thickness is modified accordingly and interpreted as a measure of the momentum of fluid trapped in the boundary layer rather than as the distance displaced laterally by the retardation of the flow in it. The result is consistent with previous specific numerical and analytical descriptions of these boundary-layer flows.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 255 , October 1993 , pp. 437 - 446
Copyright
© 1993 Cambridge University Press

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References

Bar-Lev, M. & Yang, H. T. 1975 Initial flow field over an impulsively started circular cylinder. J. Fluid Mech. 72, 625–647.Google Scholar
Batchelor, G. K. 1967 An Introduction to Fluid Dynamics. Cambridge University Press.
Blasius, H. 1908 Grenzschichten in Flüssigkeiten mit kleiner Reibung. Z. Math. Phys. 56, 1–37.Google Scholar
Collins, W. M. & Dennis, S. C. R. 1973 The initial flow past an impulsively started circular cylinder. Q. J. Mech. Appl. Maths 26, 53–75.Google Scholar
Jeffreys, H. & Jeffreys, B. S. 1978 Methods of Mathematical Physics, 3rd edn. Cambridge University Press.
Lighthill, M. J. 1958 On displacement thickness. J. Fluid Mech. 4, 383–392.Google Scholar
Lighthill, M. J. 1963 Introduction. Boundary layer theory. In Laminar Boundary Layers (ed. L. Rosenhead), chap. II. Oxford University Press.
Milne-Thomson, L. M. 1968 Theoretical Hydrodynamics, 5th edn. Macmillan.
Schlichting, H. 1979 Boundary Layer Theory, 7th edn. McGraw-Hill.
Smith, P. A. & Stansby, P. K. 1988 Impulsively started flow around a circular cylinder by the vortex method. J. Fluid Mech. 194, 45–77.Google Scholar
Stuart, J. T. 1963 Unsteady boundary layers. In Laminar Boundary Layers (ed. L. Rosenhead), chap. VII. Oxford University Press.
Wang, C.-Y. 1968 On high-frequency oscillatory viscous flows. J. Fluid Mech. 32, 55–68.Google Scholar
White, F. M. 1991 Viscous Fluid Flow, 2nd edn. McGraw-Hill.