Turbulent boundary layer structure near a bounding wall is to be studied experimentally and through numerical simulation. The experimental tools will be a miniaturized nine-sensor hot-wire probe which can measure both velocity and vorticity, as well as flow visualization. The focus is on elucidating the complex three- dimensional vortex structures known to exist in turbulent flow past a surface. Both smooth surfaces, as well as those modified by riblets, will be studied. Riblets are known to produce drag-reducing effects, but the mechanism responsible for this is as yet not understood. This study will advance the understanding, prediction, and control of this effect.
