Tower shadow effect

A practical example of obstacle-induced flow in the atmosphere that constitutes a substantial meteorological measurement problem is the ‘wind shadow’ effect of a meteorological tower on wind velocity in the lee of the structure. At White Sands Missile Range, New Mexico, a 150-meter tower is utilized to obtain ballistic winds in the lower part of the planetary boundary layer. An experiment has been conducted concerning the flow around a 1:4 scale model section of the tower in the subsonic wind tunnel at the Fluid Dynamics Laboratory, Colorado State University (CSU), Fort Collins, Colorado. Comparison of field results and experiment suggests a maximum wind decrement of 40% in the tower wake at a distance of 3.6 meters. Wind decrements of 10% or greater at this distance are confined to a 30-degree sector in the wake of the fully instrumented tower.