ESDU 82026
Strong winds in the atmospheric boundary layer. Part 1: hourlymean wind speeds.
Abstract:
ESDU 82026 provides methods for estimating the variation of strong hourlymean wind speeds in the atmospheric boundary layer. The data are particularly applicable in calculations of wind loads on buildings and structures. The range of applicability includes heights between ground level and the edge of the Earth's boundary layer (5003000 m) over various types of terrain including those where step changes in surface roughness occur upwind of the site.The methods described, and summarised in calculation sheets, start with a known reference wind speed applicable for a specified terrain and height such as taken from a map of extreme wind speeds. Factors are then given by which this value must be multiplied to account for the terrain roughness at the site in question, for changes in terrain upwind of the site and for different heights above the ground. Separate statistical factors are given to account for return periods and risk of exceedance other than those applicable to the reference wind speed. Guidance on topographical effects is given such as those produced by embankments and escarpments. For the UK a map of the oncein50year hourlymean wind speed is provided, together with factors giving the equivalent directional extremes in 30 degree sectors. Sources are provided of extreme wind speed data in other countries.The full methods for estimating the effect on mean wind speed of terrain roughness changes, height above ground (and topography) are built into the computer program VIEWpac E0108 described in ESDU 01008.Indexed under:
Details:
Data Item ESDU 82026  

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This Data Item contains 10 interactive graph(s) as listed below.
Graph  Title 

Figure 2  The Factor K_{N} 
Figure 3  Zeroplane displacement height 
Figure 4  The Factor K_{s*} 
Figure 5  The Factor K_{s} 
Figure 6  Part 1  The Factor K_{z*} = V_{z*}/u_{*} (equilibrium boundary layer) 
Figure 6  Part 2  The Factor K_{z*} = V_{z*}/u_{*} (equilibrium boundary layer) 
Figure 7  Part 1  The Factor K_{z}* = V_{z}/V_{10} (equilibrium boundary layer) 
Figure 7  Part 2  The Factor K_{z}* = V_{z}/V_{10} (equilibrium boundary layer) 
Figure 8a  The Factor K_{x} for z ≤ h_{i}. z_{0} > z_{01} 
Figure 8b  The Factor K_{x} for z ≤ h_{i}. z_{0} < z_{01} 