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On the displacement height in the logarithmic velocity profile

  • P. S. Jackson (a1)
Abstract

The displacement height appears in the logarithmic velocity profile for rough-wall boundary layers as a reference height for the vertical co-ordinate. It is shown that this height should be regarded as the level at which the mean drag on the surface appears to act. The equations of motion then show that this also coincides with the average displacement thickness for the shear stress.

A simple analytical model, experimental results and dimensional analysis are all used to indicate how the displacement height depends upon the detailed geometry of the roughness elements.

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References
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Blihco, R. G. & Partheniades, E. 1971 Turbulence characteristics in free surface flows over smooth and rough boundaries. J. Hyd. Res. 9, 4369.
Cionco, R. M. 1972 A wind-profile index for canopy flow. Boundary-Layer Met. 3, 225263.
Counihan, J. 1971 Wind tunnel determination of the roughness length as a function of the fetch and the roughness density of three dimensional elements. Atmos. Environ. 5, 637642.
Grass, A. J. 1971 Structural features of turbulent flow over smooth and rough boundaries. J. Fluid Mech. 50, 233255.
Inoue, E. 1963 On the turbulent structure of airflow within crop canopies. J. Met. Soc. Japan 41, 317326.
Kamphius, J. W. 1974 Determination of sand roughness for fixed beds. J. Hyd. Res. 12, 193203.
Kondo, J. 1971 Relationship between the roughness coefficient and other aerodynamic parameters. J. Met. Soc. Japan 49, 121124.
Lee, B. E. & Soliman, B. F. 1977 An investigation of the forces on three-dimensional bluff bodies in rough wall turbulent boundary layers. Trans. A.S.M.E. I, J. Fluids Engng 99, 503510.
Oke, T. R. 1974 Review of urban climatology, 1968–1973. W.M.O. Tech. Note no. 134.
O'Loughlin, E. M. & Annambhotla, V. S. 1969 Flow phenomena near rough boundaries. J. Hyd. Res. 7, 231250.
Perry, A. E., Schofield, W. H. & Joubert, P. N. 1969 Rough wall turbulent boundary layers. J. Fluid Mech. 37, 383413.
Sayre, W. W. & Albertson, M. L. 1963 Roughness spacing in rigid open channels. Trans. A.S.C.E. 128, 343427.
Stanhill, G. 1969 A simple instrument for the field measurement of turbulent diffusion flux. J. Appl. Met. 8, 509513.
Thom, A. S. 1971 Momentum absorption by vegetation. Quart. J. Roy. Met. Soc. 97, 414428.
Townsend, A. A. 1976 The Structure of Turbulent Shear Flow, 2nd edn. Cambridge University Press.
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Journal of Fluid Mechanics
  • ISSN: 0022-1120
  • EISSN: 1469-7645
  • URL: /core/journals/journal-of-fluid-mechanics
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