Abstract
A wind-tunnel investigation of the wind flow over two-dimensional forward-facing escarpments is reported as part of a continuing research programme into the effects of local topography on the wind flow close to the ground. Four sharp-edged escarpments with their slopes varying between a cliff and a 4:1 gradient, were placed normal to a simulated neutrally-stable rural boundary layer which was modelled to a scale of 1:300. The resulting flows close to the surfaces of the escarpments were measured with a hot-wire anemometer. The modifications to the mean wind speed, turbulence intensity and energy spectra over the escarpments are described. The results indicate the extent and magnitude of the modification to the flow and suggest that significant changes in turbulence characteristics only occur in the wake region close behind the crest, where a shift of energy to higher frequencies is evident.
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Bowen, A. J. and Lindley, D.: 1974, ‘Measurements of the Mean Wind Flow Over Various Escarpment Shapes’, Proc. Fifth Australasian Conference on Hydraulics and Fluid Mechanics, University of Canterbury, N.Z., Dec. 1974, pp. 211–219.
British Standard CP3: 1972, Chapter V, Code of Basic Data for the Design of Buildings, Part 2, Windloads.
de Bray, B.G.: 1973, ‘Atmospheric Shear Flows Over Ramps and Escarpments’, Industrial Aerodynamics Abstracts 5, Sept.–Oct. 1973.
ESDU 72026: 1972, ‘Characteristics of Wind Speed in the Lower Layers of the Atmosphere near the Ground; Strong Winds (Neutral Atmosphere)’, Engineering Sciences Data Unit, London.
ESDU 74031: 1974, ‘Characteristics of Atmospheric Turbulence near the Ground’, Engineering Sciences Data Unit, London.
Freeston, D. H.: 1974, ‘Atmospheric Shear Flows Over Ramps and Escarpments’, Presented to the Fifth Australasian Conference on Hydraulics and Fluid Mechanics, University of Canterbury, N.Z., Dec. 1974. Available from Mechanical Engineering Dept., University of Auckland.
Jackson, P. S.: 1975, ‘A Theory for Flow Over Escarpments’, Proc. Fourth International Conference on Wind Effects on Buildings and Structures, Heathrow, U.K., September 1975. Cambridge University Press.
Lindley, D., Bowen, A. J., and Morfee, P.: 1974, ‘A Propeller Anemometer For a Digital Wind Data Acquisition System’, Proc. Fifth Australasian Conference on Hydraulics and Fluid Mechanics, University of Canterbury, N.Z., Dec. 1974, pp. 258–268.
Lindley, D., Bowen, A. J., and Morfee, P.: 1974, ‘A Propeller Anemometer For a Digital Wind Data Atmospheric Boundary Layer’, The Seventh CIB Congress and General Assembly, Edinburgh, Sept. 1977.
Mitsuta, Y.: 1971, ‘Characteristics of Airflow over the Barriers in the Storm’, Proc. Third International Conference on Wind Effects on Buildings and Structures, Tokyo, 1971, pp. 33–44.
New Zealand Standard 4203: 1976, New Zealand Standard Code of Practice for General Structural Design and Design Loadings for Buildings.
Raine, J. K.: 1974, ‘Simulation of a Neutrally Stable Rural Atmospheric Boundary Layer in a Wind Tunnel’, Proc. Fifth Australasian Conference on Hydraulics and Fluid Mechanics, University of Canterbury, N.Z., Dec. 1974, pp. 190–199.
Sacre, C.: 1973, ‘Influence d'une Colline sur la Vitesse du Vent dans la Couche Limite de Surface’, Internal Report, Centre Scientifique et Technique du Batiment, Nantes, France.
WMO: 1964, Sites for Wind Power Installations, Technical Note No. 63, World Meteorological Organisation, Geneva.
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Bowen, A.J., Lindley, D. A wind-tunnel investigation of the wind speed and turbulence characteristics close to the ground over various escarpment shapes. Boundary-Layer Meteorol 12, 259–271 (1977). https://doi.org/10.1007/BF00121466
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DOI: https://doi.org/10.1007/BF00121466