Characteristics of atmospheric turbulence near the ground. Part III: variations in space and time for strong winds (neutral atmosphere). (Incorporates A@ B@ C@ D@ and E)
ESDU 86010 is the third in a group providing comprehensive atmospheric turbulence characteristics@ and deals with the relationship between values measured at two points in space of the three turbulence velocity components. It covers joint-probability@ cross-correlations@ coherence and phase angle (giving cross-spectral densities) and integral length scales of all turbulence components in any direction. The data apply throughout the atmospheric boundary layer and for different types of terrain. Since the length scales are all related to that for the along-wind component in the along-wind direction@ effects of roughness changes on all components can be accounted for through their effect on that length scale predicted using ESDU 85020. The data were derived from the von Karman equations modified to take account of the distorting (anisotropic) effects near the ground. The theoretical basis allows rational extrapolation from measurements made at moderate wind speeds to the much higher design speed case when@ in particular@ much longer length scales are obtained.