Analysis of gust structure in the atmospheric boundary layer by using conditional sampling

A conditional sampling scheme used to detect events characterized by a high level of short time variance is assessed for use in detecting gusts. The conditionally sampled average of the longitudinal velocity component exhibits a typical structure, a gust. This structure is similar to the bursts in turbulent boundary layers. The frequency of occurrence and the time scale of the gusts are determined by the same variables as the bursts, i.e., the outer variables free stream velocity and surface layer thickness. The technique was compared with wind measurements carried out at a fixed point. The structure and frequency of gusts are predicted accurately.