Boundary-Layer Meteorology

, Volume 107, Issue 2, pp 445–468

Drag Partition for Regularly-Arrayed Rough Surfaces

  • D. M. Crawley
  • W. G. Nickling


Vegetation and other roughness elements distributed across a surface can providesignificant protection against wind erosion by extracting momentum from the flowand thereby reducing the shear stress acting at the surface. A theoretical model haspreviously been presented to specify the partition of drag forces for rough surfacesand to predict required vegetation density to suppress wind erosion. However, themodel parameters have not yet been constrained and the predictive capacity of themodel has remained uncertain. A wind-tunnel study was conducted to measure thedrag partition for a range of roughness densities and to parameterise the model inorder to improve its range of potential applicability. The drag forces acting on bothan array of roughness elements and the intervening surface were measured independentlyand simultaneously using new drag balance instrumentation. A detailed measure of thespatial heterogeneity of surface shear stresses was also made using Irwin sensors. Thedata agreed well with previous results and confirmed the general form of the model.Analysis of the drag partition confirmed the parameter definition β = CR/CS(where CR and CS are roughness element and surface drag coefficients,respectively) and a constant proportional difference between the mean and maximumsurface shear stress was found. The results of this experiment suggest that the definitionfor m, the surface shear stress inhomogeneity parameter, should be revised, although thetheoretical and physical reasons for including this parameter in the model appear to bevalid. Best-fit values for m ranged from 0.53 to 0.58.

Drag partition Roughness arrays Shear stress Shear stress partitioning Wind erosion 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Bradley, E. F.: 1968, 'A Shearing Stress Meter for Micrometeorological Studies', Quart. J. Roy. Meteorol. Soc. 94, 380–387.Google Scholar
  2. Gillette, D. A. and Stockton, P. H.: 1989, 'The Effect of Nonerodible Particles on Wind Erosion of Erodible Surfaces', J. Geophys. Res. 94, 12885–12893.Google Scholar
  3. Gillies, J. A.: 1994, A Wind Tunnel Study of the Relationship Between Complex Surface Roughness Form, Flow Geometry and Shearing Stress, Ph.D. Dissertation, University of Guelph, Canada, 231 pp.Google Scholar
  4. Gillies, J. A., Lancaster, N., Nickling, W. G., and Crawley, D. M.: 2000, 'Field Determination of Drag Forces and Shear Stress Partitioning Effects for a Desert Shrub (Sarcobatus vermiculatus, Greasewood)', J. Geophys. Res. 105, 24871–24880.Google Scholar
  5. Grant, P. F. and Nickling, W. G.: 1998, 'Direct Field Measurement of Wind Drag on Vegetation for Application to Windbreak Design and Modelling', Land Degrad. Dev. 9, 57–66.Google Scholar
  6. Irwin, H. P. A. H.: 1980, 'A simple Omnidirectional Sensor for Wind-Tunnel Studies of Pedestrian Level Winds', J. Wind Eng. Ind. Aerodyn. 7, 219–239.Google Scholar
  7. Iversen, J. D., Wang, W. P., Rasmussen, K. R., Mikkelson, H. E., and Leach, R. N.: 1991, 'Roughness Element Effect on Local and Universal Saltation Transport', Acta Mech. Suppl. 2, 65–75.Google Scholar
  8. Kaimal, J. C. and Finnigan, J. J.: 1994, Atmospheric Boundary Layer Flows: Their Structure and Measurement, Oxford University Press, New York, 283 pp.Google Scholar
  9. Kutzbach, J. E.: 1961, 'Investigation of the Modification of Wind Profiles by Artificially Controlled Surface Roughness', in Studies of Three-Dimensional Structure of the Planetary Boundary Layer, Annual Report Contract DA 36–039–SC-80282.Department of Meteorology, University of Wisconsin, Madison, WI, pp. 71–113.Google Scholar
  10. Lancaster, N. and Baas, A.: 1998, 'Influence of Vegetation Cover on Sand Transport by Wind: Field Studies at Owens Lake, California', Earth Surf. Proc. Landforms 23, 69–82.Google Scholar
  11. Lyles, L. and Allison, B. E.: 1976, 'Wind Erosion: The Protective Role of Simulated Standing Stubble', Trans. AMSE 19, 61–64.Google Scholar
  12. Lyles, L., Schrandt, R. L., and Schmeidler, N. F.: 1974, 'How Aerodynamics Roughness Elements Control Sand Movement', Trans. AMSE 17, 134–139.Google Scholar
  13. Marshall, J. K.: 1971, 'Drag Measurements in Roughness Arrays of Varying Density and Distribution', Agric. Meteorol. 8, 269–292.Google Scholar
  14. McKenna Neuman, C.: 1998, 'Particle Transport and Adjustments of the Boundary Layer over Rough Surfaces with an Unrestricted, Upwind Supply of Sediment', Geomorphology 25, 1–17.Google Scholar
  15. McKenna Neuman, C. and Nickling, W. G.: 1994, 'Momentum Extraction with Saltation: Implications for Experimental Evaluation of Wind Profile Parameters', Boundary-Layer Meteorol. 68, 35–50.Google Scholar
  16. Monteiro, J. P. and Viegas, D. X.: 1996, 'On the Use of Irwin and PrestonWall Shear Stress Probes in Turbulent Incompressible Flows with Pressure Gradients', J. Wind Eng. Ind. Aerodyn. 64, 15–29.Google Scholar
  17. Musick, H. B. and Gillette, D. A.: 1990, 'Field Evaluation of Relationships between a Vegetated Structural Parameter and Sheltering against Wind Erosion', Land Degrad. Rehabil. 2, 87–94.Google Scholar
  18. Musick, H. B., Trujillo, S. M., and Truman, C. R.: 1996, 'Wind-Tunnel Modelling of the Influence of Vegetation Structure on Saltation Threshold', Earth Surf. Proc. Landforms 21, 589–605.Google Scholar
  19. Nemoto, M. and Nishimura, K.: 2001, 'Direct Measurement of Shear Stress during Snow Saltation', Boundary-Layer Meteorol. 100, 149–170.Google Scholar
  20. Nickling, W. G. and McKenna Neuman, C.: 1995, 'Development of Desert Lag Surfaces', Sedimentology 42, 403–414.Google Scholar
  21. Nickling, W. G., Gillies, J. A., Lancaster, N., and Crawley, D. M.: 1999, Optimizing Managed Vegetation Planting Configurations at Owens Lake, California, Final Technical Report to Great Basin Unified Air pollution Control District, Bishop, CA, 76 pp.Google Scholar
  22. Nielson, D. C. and Aiken, R. M.: 1998, 'Wind Speed above and within Sunflower Stalks Varying in Height and Population', J. Soil Water Cons. 53, 347–352.Google Scholar
  23. Prandtl, L.: 1932, 'Zur turbulenten Strömung in Röhren und längs Platten', Ergebn. Aerdyn. Versuchsanst. 4, 18–29.Google Scholar
  24. Raupach, M. R.: 1992, 'Drag and Drag Partition on Rough Surfaces', Boundary-Layer Meteorol. 60, 375–395.Google Scholar
  25. Raupach, M. R., Gillette, D. A., and Leys, J. F.: 1993, 'The Effect of Roughness Elements on Wind Erosion Threshold', J. Geophys. Res. 98, 3023–3029.Google Scholar
  26. Raupach, M. R., Thom, A. S., and Edwards, I.: 1980, 'AWind-Tunnel Study of Turbulent Flow Close to Regularly Arrayed Rough Surfaces', Boundary-Layer Meteorol. 18, 373–397.Google Scholar
  27. Schlichting, H.: 1936,'Experimentelle Untersuchungen zum Rauhigkeitsproblem', Ingen.-Arch. 7, 1–34; NACA Tech. Mem. 823.Google Scholar
  28. Siddoway, F. H., Chepil, W. S., and Armbrust, D. V.: 1965, 'Effect of Kind, Amount, and Placement of Residue on Wind Erosion Control', Trans. AMSE 8, 327–331.Google Scholar
  29. Stacey, G. R., Belcher, R. E., and Wood, C. J.: 1994, 'Wind Flows and Forces in a Model Spruce Forest', Boundary-Layer Meteorol. 69, 311–334.Google Scholar
  30. Stockton, P. H. and Gillette, D. A.: 1990, 'Field Measurement of the Sheltering Effect of Vegetation on Erodible Land Surfaces', Land Degrad. Rehabil. 2, 77–85.Google Scholar
  31. Taylor, P. A.: 1988, 'Turbulent Wakes in the Atmospheric Boundary Layer', W. L. Steffen and O. T. Denmead (eds.), Flow and Transport in the Natural Environment: Advances and Applications, Springer-Verlag, Berlin, 270–292.Google Scholar
  32. Thom, A. S.: 1971, 'Momentum Absorption by Vegetation', Quart. J. Roy. Meteorol. Soc. 97, 414–428.Google Scholar
  33. Wolfe, S. A. and Nickling, W. G.: 1993, 'The Protective Role of Sparse Vegetation inWind Erosion', Prog. Phys. Geog. 17, 50–68.Google Scholar
  34. Wolfe, S. A. and Nickling, W. G.: 1996, 'Shear Stress Partitioning in Sparsely Vegetated Desert Canopies', Earth Surf. Proc. Landforms 21, 607–619.Google Scholar
  35. Wu, H. and Stathopoulos, T.: 1994, 'Further Experiments on Irwin's Surface Wind Sensor', J. Wind Eng. Ind. Aerodyn. 53, 441–452.Google Scholar
  36. Wyatt, V. E. and Nickling, W. G.: 1997, 'Drag and Shear Stress Partitioning in Sparse Desert-Creosote Communities', Can. J. Earth Sci. 34, 1486–1498.Google Scholar

Copyright information

© Kluwer Academic Publishers 2003

Authors and Affiliations

  • D. M. Crawley
    • 1
  • W. G. Nickling
    • 1
  1. 1.Wind Erosion Laboratory, Department of GeographyUniversity of GuelphGuelph, OntarioCanada

Personalised recommendations