Skip to main content
SpringerLink
Log in

Momentum extraction with saltation: Implications for experimental evaluation of wind profile parameters

  • Published:
Boundary-Layer Meteorology Aims and scope Submit manuscript

Abstract

In wind tunnel studies of aeolian transport, the number and position of pitot tubes are decided by the researcher, so that there are important variations in the computation ofU * between studies. Velocity measurements seldom are made very close to mobile surfaces because the tubes become blocked by drifting sand grains. This practice is fortuitous as demonstrated by recent selfregulatory models of saltation which indicate that fluid and grain-borne shear stress vary substantially within the lowest 0.01 m and application of the logarithmic law is therefore unsound. This study reports detailed velocity measurements which further suggest that no single logarithmic expression, based on fixed values of κ and τ, adequately represents the full wind profile which includes the inner saltation cloud above 0.01 m and the outer grain-free region of the boundary layer. A much improved fit over the logarithmic wind profile model is achieved with a square root relation, although there is no known physical basis for this specific form of power model. Relatively shallow boundary-layer development in wind tunnels forces the velocity gradient above the region of momentum extraction to attain exceptionally large values, uncommon in natural settings.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

Abbreviations

U * :

shear velocity

U *1 :

threshold shear velocity

τ:

shear stress

U z :

velocity atZ

U 1z :

velocity atZ, standardized byU f

U t :

threshold velocity atk′

U f :

free-stream velocity

D :

mean grain diameter

ϕ:

unit of grain size (−log2 D)

l 1 :

mixing length at unit height

Z :

height above surface

Z 0 :

roughness length

k′:

focus height

H :

wind tunnel height

d :

height of the internal boundary layer

α,c, C, D′:

empirical coefficients

F :

Froude number

F c :

Cole's wake function

κ:

von Karman's constant

p :

exponent

C D :

drag coefficient

g :

gravitational acceleration

∈y :

standard error of velocity estimate

Q :

sediment flux

References

  • Anderson, R. S.: 1987, ‘A Theoretical Model for Aeolian Impact Ripples’,Sedimentology 35, 175–188.

    Google Scholar 

  • Anderson, R. S. and Haff, P. K.: 1991, ‘Wind Modification and Bed Response during Saltation of Sand in Air’,Acta Mechanica Supplementum 1, 21–52.

    Google Scholar 

  • Bagnold, R. A.: 1941,The Physics of Blown Sand and Desert Dunes, Methuen, London, 265 pp.

    Google Scholar 

  • Belly, P.-Y.: 1964,Sand Movement by Wind, US Army Corps of Engineers, Coastal Engineering Research Center, Technical Memorandum I.

  • Cole, D.: 1956, ‘The Law of the Wake in the Turbulent Boundary Layer’,J. Fluid Mech. 1, 191–226.

    Google Scholar 

  • Coleman, N. L.: 1981, ‘Velocity Profiles with Suspended Sediment’,J. of Hydraulic Res. 19 (3), 211–229.

    Google Scholar 

  • Charnock, H.: 1955, ‘Wind Stress on a Water Surface’,Q. J. Royal Meteorol. Soc. 81, 639–640.

    Google Scholar 

  • Chiu, T. Y.: 1972,Sand Transport by Wind, Technical Report TR-040, Department of Coastal and Oceanographic Engineering, University of Florida.

  • Einstein, H. A. and Chien, N.: 1955,Effect of Heavy Sediment Concentration near the Bed on Velocity and Sediment Distribution. US Army Corps of Engineers, Missouri River District, Sediment Series No. 8.

    Google Scholar 

  • Finlan, C. A.: 1987, ‘The Effects of Particle Shape and Size on the Entrainment and Transport of Sand by Wind’, Unpublished M.Sc. Thesis, University of Guelph, 261 pp.

  • Gerety, K. M.: 1985, ‘Problems with Determination ofU * from Wind Velocity Profiles Measured in Experiments with Saltation’, in: O. E. Barndorff-Nielsen, J. T. Moller, K. R. Rasmussen, and B. B. Willets (eds.),Proceedings of International Workshop on the Physics of Blown Sand, pp. 271–300. Department of Theoretical Statistics, Institute of Mathematics, University of Aarhus, Memorandum 8.

  • Gillette, D. A. and Stockton, P. H.: 1989, ‘The Effect of Nonerodible Particles on Wind Erosion of Erodible Surfaces’,J. Geophys. Res. 94, 12,885–12,893.

    Google Scholar 

  • Horikawa, K. and Shen, W.: 1960,Sand Movement by Wind Action (on the Characteristics of Sand Traps). US Army Corps of Engineers, Technical Memorandum No. 119.

  • Kadib, A. L.: 1964, Addendum II:Sand Transport by Wind, Studies with Sand C (0.145 mm Diameter). US Army Corps of Engineers, Coastal Engineering Research Center, Technical Memorandum No. 1:II-1–II-10.

    Google Scholar 

  • Kawamura, R.: 1964,Study of Sand Movement by Wind, Hydraulic Engineering Technical Lab Technical Report HEL-2-8, 99–108.

  • Krumbein, W. C.: 1934, ‘Size Frequency Distribution of Sediments’,J. Sedimentary Petrology 4, 65–77.

    Google Scholar 

  • Lee, H. Y. and Yu. U. W.: 1991, ‘Velocity Prolife of Sediment-Laden Open Channel Flow’,Int. J. Sediment Research 6, 25–51.

    Google Scholar 

  • Lettau, K. and Lettau, H.: 1978, ‘Experimental and Micrometeorological Field Studies of Dune Migration, in: H. H. Lettau and K. Lettau (eds.),Exploring the World's Driest Climate, 110–147. Madison: Center for Climatic Research, University of Wisconsin.

    Google Scholar 

  • McEwan, I. K.: 1993, ‘Bagnold's Kink: A Physical Feature of a Wind Velocity Profile Modified by Blown Sand?Earth Surface Processes & Landforms 18, 145–156.

    Google Scholar 

  • McEwan, I. K. and Willetts, B. B.: 1991, ‘Numerical Model of the Saltation Cloud’,Acta Mechanica Supplementum 1, 53–66.

    Google Scholar 

  • Nikurdase, J.: 1933,Laws of Flow in Rough Pipes (1950 translation). National Advisory Committee on Aeronautics, Technical Memorandum 1292, Washington D.C.

    Google Scholar 

  • Owen, P.: 1964, ‘Saltation of Uniform Grains in Air’,J. Fluid Mech. 20 (2), 225–242.

    Google Scholar 

  • Owen, P. and Gillette, D.: 1985, ‘Wind Tunnel Constraint on Saltation’, in: O. E. Barndorff-Nielsen, J. T. Moller, K. R. Rasmussen, and B. B. Willetts (eds.),Proceedings of International Workshop on the Physics of Blown Sand, pp. 253–269, Department of Theoretical Statistics, Institute of Mathematics, University of Aarhus, Mem. 8.

  • Prandtl, L.: 1935, ‘The Mechanics of Viscous Fluids’, in: W. F. Durand (ed.),Aerodynamic Theory, Vol. III, pp. 34–208. Springer, Berlin.

    Google Scholar 

  • Schlichting, H.: 1968,Boundary Layer Theory, McGraw-Hill, New York. 747 pp.

    Google Scholar 

  • Sherman, D. J.: 1992, ‘An Equilibrium Relationship for Shear Velocity and Apparent Roughness Length in Aeolian Saltation’,Geomorphology 5, 419–431.

    Google Scholar 

  • Sherman, D. J. and Greenwood, B.: 1984, ‘Boundary Roughness and Bedforms in the Surf Zone’,Marine Geology 60, 199–218.

    Google Scholar 

  • Sutton, O. G.: 1953,Micrometeorology, Krieger, Florida, 333 pp.

    Google Scholar 

  • Walker, J. D. and Southard, J. B.: 1982, ‘Experimental Study of Sand Ripples’, in:Abstracts of the 11th International Association of Sedimentologists Congress, Hamilton, Ontario, 65.

  • White, B. R.: 1979, ‘Soil Transport by Wind on Mars’,J. Geophys. Res 84, 4643–4651.

    Google Scholar 

  • Willetts, B.: 1983, ‘Transport by Wind of Granular Materials of Different Grain Shapes and Densities’,Sedimentology 30, 669–679.

    Google Scholar 

  • Zingg, A. W.: 1953, ‘Wind Tunnel Studies of the Movement of Sedimentary Material’, in:Proceedings of the 5th Hydraulics Conference Bulletin, pp. 111–135, Iowa State University, Studies in Engineering, 34.

Download references

Author information

Authors and Affiliations

  1. Department of Geography, Trent University, K9J 7B8, Peterborough, Ontario, Canada

    C. McKenna Neuman

  2. Department of Geography, University of Guelph, N1G 2W1, Guelph, Ontario, Canada

    W. G. Nickling

Authors
  1. C. McKenna Neuman
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. W. G. Nickling
    View author publications

    You can also search for this author in PubMed Google Scholar

Additional information

All lengths in m, velocities in m s−1, and fluxes in kg m−1 s−1 unless otherwise stated. All velocities are time averaged. The bed condition is indicated by the additional subscripts:m (mobile) and s (stable).

Rights and permissions

Reprints and permissions

About this article

Cite this article

Neuman, C.M., Nickling, W.G. Momentum extraction with saltation: Implications for experimental evaluation of wind profile parameters. Boundary-Layer Meteorol 68, 35–50 (1994). https://doi.org/10.1007/BF00712663

Download citation

  • Revised:

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF00712663

Keywords

Search

Navigation