Effects of the Shedding Vortices on the Grand Wall Flow behind a Three-Dimensional Protuberance

Abstract

The vortex structure around a rectangular plate standing vertically on the flat wall where the laminar boundary layer was developing was examined by visualization technique. The structure of the vortices shed from the rectangular plates of w/h=0.5, 1 and 3 can be classified into four patterns A-D in terms of both the Reynolds number Rew and the ratio of plate height to boundary layer thickness h/δ. The pattern A shows the horseshoe trailing vortex, the pattern B shows a pair of trailing vortices, the pattern C shows the symmetrical hairpin vortices, and the pattern D shows the irregular hairpin vortices. It seems that the mean flow patterns on the grand wall behind the rectangular plates are closely related with four types of the vortex structure shed from those plates.