WIND TUNNEL MEASUREMENTS OF THREE-DIMENSIONAL WAKES OF BUILDINGS.

Measurements relevant to the effect of buildings on the low-level atmospheric boundary layer are presented. A wind tunnel experiment was undertaken to determine the nature of the flow downstream from a gap between two transversely aligned, equal-sized models of rectangular cross section. These building models were immersed in an equilibrium turbulent boundary layer which was developed on a smooth floor in a zero longitudinal pressure gradient. Measurements with an inclined (45-degree) hot-wire made at key position downstream of models arranged with large, small, and no gaps between them. Hot-wire theory is presented which enables computation of the three mean velocity components, U, V and W, as well as Reynolds stresses. These measurements permit understanding of the character of the wake downstream of laterally spaced buildings. Surface stream line patterns obtained by the oil-film method were used to delineate the separation region to the rear of the buildings for a variety of spacings.