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Environmental Fluid Mechanics

, Volume 4, Issue 4, pp 367–383 | Cite as

Estimation of the surface stress from the streamwise pressure gradient: The Kármán Integral Momentum Equation revisited

  • P. A. Findlater
  • W. D. Scott
  • S. E. Greenhill
  • J. M. Hopwood
Article
  • 64 Downloads

Abstract

A method is developed to estimate the stress at the surface in a portable wind tunnel for wind erosion studies. The boundary layer height and the pressure gradient are used in a simple expression from the Kármán Integral Momentum Equation. Values of friction velocity u* are within 10% of experimental values obtained through correlation techniques, including measurements of differential pressures with the Murdoch Turbulence Probe MTP and the X-wire, hot-wire anemometer XWA. Wind velocity and stress profiles reveal logarithmic trends and a ‘constant stress layer’ near the surface in the DAWA portable wind tunnel. Realignment of the statistics with the mean wind is essential.

Key words

agriculture cross-wire erosion hot-wire integral Kármán karman momentum Murdoch Turbulence Probe shear stress wind tunnel 

Abbreviations

DAWA

Department of Agriculture, Western Australia-formerly, West Australian Department of Agriculture and also Agriculture WA

MTP

Murdoch Turbulence Probe

XWA

X-Wire Anemometer, a cross-wire, hot-wire anemometer

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Copyright information

© Kluwer Academic Publishers 2004

Authors and Affiliations

  • P. A. Findlater
    • 1
  • W. D. Scott
    • 2
  • S. E. Greenhill
    • 2
  • J. M. Hopwood
    • 3
  1. 1.Department of AgricultureWestern AustraliaGeraldton
  2. 2.Murdoch UniversityMurdoch
  3. 3.University of Western AustraliaCrawley

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