Abstract
A knowledge of the nature of turbulent flow over very rough surfaces is important for an understanding of the environment of crops, forests, and cities. For this reason, a wind-tunnel investigation was carried out on the variations in mean velocity, Reynolds shear-stress, and other turbulence quantities in a deep turbulent flow over a rough surface having a fair degree of randomness in the shapes, sizes, and positions of its elements.
There was a layer close to the surface with considerable variations in both mean velocity and shear-stress, and the horizontal scale over which the mean velocity varied was much larger than the average distance between roughness elements. Above this layer, whose depth was of the order of the spacing between roughness elements, shear stress was constant with height, and the velocity profile had a logarithmic form. The usefulness of both mean profile and eddy-correlation methods for estimating fluxes above very rough terrain is discussed in the light of these findings.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Antonia, R. A. and Luxton, R. E.: 1971, ‘The Response of a Turbulent Boundary Layer to a Step Change in Surface Roughness. Part 1. Smooth to Rough’, J. Fluid Mech. 48, 721–761.
Bendat, J. S. and Piersol, A. G.: 1971, Random Data: Analysis and Measurement Procedures, Wiley-Interscience, New York, U.S.A..
Blake, W. K.: 1972, ‘Turbulent Velocity and Pressure Fields in Boundary-Layer Flows Over Rough Surfaces’, in J. L. Zakin and G. K. Patterson (eds), Symposium on Turbulence in Liquids, 1971, pp. 114–122, University of Missouri, Rolla.
Busch, N. E.: 1973, ‘Introductory Lecture on the Mechanics of Atmospheric Turbulence’, In D. A. Haugen (ed), Workshop on Micrometeorology, 1972, American Meteorological Society.
Busch, N. E. and Panofsky, H. A.: 1968, ‘Recent Spectra of Atmospheric Turbulence’, Quart. J. Roy. Meteorol. Soc. 94, 132–148.
Businger, J. A., Wyngaard, J. C., and Bradley, E. F.: 1971, ‘Flux-profile Relationships in the Atmospheric Surface Layer’, J. Atmos. Sci. 28, 181–189.
Chanda, B. 1958, ‘Turbulent Boundary Layer Over Heated and Unheated, Plane, Rough Surfaces’, Colorado State University, Sci. Rept. 1 CER58BC21.
Chen, C. K. and Roberson, J. A.: 1974, ‘Turbulence in Wakes of Roughness Elements’, Journal of the Hydraulics Division, American Society of Civil Engineers 100, 53–67.
Counihan, J.: 1975, ‘Adiabatic Atmospheric Boundary Layers: A Review and Analysis of Data from the Period 1880–1972’, Atmos. Environ. 9, 871–905.
Counihan, J., Hunt, J. C. R., and Jackson, P. S.: 1974, ‘Wakes behind Two-dimensional Surface Obstacles in Turbulent Boundary Layers’, J. Fluid Mech. 64, 529–563.
Ford, E. D.: 1976, ‘The Canopy of a Scots Pine Forest: Description of a Surface of Complex Roughness’, Agric. Meteorol. 17, 9–32.
Gash, J. H. C., and Stewart, J. B.: 1975, ‘The Average Surface Resistance of a Pine Forest Derived from Bowen Ratio Measurements’, Boundary-Layer Meteorol. 8, 453–464.
Graetz, R. C.: 1972, ‘Aspects of the Micrometeorology of a Patterned Plant Community’, Ph.D. thesis, Dept. of Envir. Biol. Res., Sch. Biol. Sci. Australian National University, Canberra, Australia.
Izumi, Y.: 1971, ‘Kansas 1968 Field Program Data Report’, Environ. Res. Pap. 379, Air Force Cambridge Res. Lab., Cambridge, Mass. 79 pp.
Lynch, R. A. and Bradley, E. F.: 1974, ‘Shearing Stress Meter’, J. Appl. Meteorol. 13, 588–591.
Makita H.: 1968, ‘Response of a Turbulent Boundary Layer to a Sudden Change in Surface Roughness’, M. Eng. thesis, University of Tokyo.
McNeil, D. D. and Shuttleworth, W. J.: 1975, ‘Comparative Measurements of the Energy Fluxes over a Pine Forest’, Boundary-Layer Meteorol. 9, 297–313.
Mulhearn, P. J., Banks, H. J., Finnigan, J. J., and Annis, P. C.: 1976, ‘Wind Forces and their Influence on Gas Loss from Grain Storage Structures’, J. Stored Prod. Res. 12, 129–142.
Mulhearn, P. J.: 1978, ‘A Wind-Tunnel Boundary Layer Study of the Effects of a Surface Roughness Change: Rough to Smooth’, Boundary-Layer Meteorol. (In press.)
Mulhearn, P. J.: 1978a, ‘Turbulent Flow over a Periodic Rough Surface’, Phys. Fluids (In press.)
Mulhearn, P. J. and Finnigan, J. J.: 1978, ‘A Simple Device for Dynamic Testing of X-Configuration Hot-Wire Anemometer Probes’, J. of Phys. E, Scientific Instruments. (In press.)
O'Loughlin, E. M.: 1965, ‘Resistance to Flow over Boundaries with Small Roughness Concentrations’, Ph.D. thesis, University of Iowa.
Panofsky, H. A.: 1974, ‘The Atmospheric Boundary Layer Below 150 Meters’, Ann. Rev. Fl. Mech. 6, 147–177.
Pasquill, F.: 1972, ‘Some Aspects of Boundary Layer Description’, Quart. J. Roy. Meteorol. Soc. 98, 469–494.
Perrier, E. R., Robertson, J. M., Millington, R. J., and Peters, D. B.: 1972, ‘Spatial and Temporal Variation of Wind Above and Within a Soybean Canopy’, Agric. Meteorol. 10, 421–442.
Seguin, B.: 1973, ‘Rugosité du paysage et diffusion atmosphérique. Étude théoretique à partir des équations de Sutton’, Atmos. Environ. 7, 429–442.
Seguin, B. and Gignoux, N.: 1974, ‘'étude expérimentale de l'influence d'un réseau de brise-vent sur le profil vertical de vitesse du vent’, Agric. Meteorol. 13, 15–23.
Tennekes, H., and Lumley, J. L.: 1972 A First Course in Turbulence, MIT Press, Cambridge, Mass., 300 pp.
Thom, A. S., Stewart, J. B., Oliver, H. R., and Gash, J. H. C.: 1975, ‘Comparison of Aerodynamic and Energy Budget Estimates of Fluxes over a Pine Forest’, Quart. J. Roy. Meteorol. Soc. 101, 93–105.
Wooding, R. A.: 1968, ‘A Low-Speed Wind Tunnel for Model Studies in Micrometeorology’, CSIRO Div. Plant. Ind. Tech. Paper No. 25. 39 pp.
Yeh, Z. and Nickerson, E. C.: 1970, ‘Airflow over Roughness Discontinuity’, Colorado State Univ. Rept. No. CER70-71FFY-ECN6. 128 pp.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Mulhearn, P.J., Finnigan, J.J. Turbulent flow over a very rough, random surface. Boundary-Layer Meteorol 15, 109–132 (1978). https://doi.org/10.1007/BF00165509
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00165509