Two-dimensional flow field behind perforated plates on a flat surface

The wind tunnel experiments were conducted under highly turbulent and disturbed flow conditions over a solid/perforated plate with a long splitter plate in its plane of symmetry. The effect of plate perforation on the formation of separation bubble and its gradual disappearance was studied. The mean velocity measurements and surface mean pressure distributions were measured after preliminary flow visualization studies. The normal plate perforation level was varied from 0%–50% to give different levels of fluid interaction into the otherwise stable bubble that exists for a solid normal plate (0% perforation level). The Reynolds number based on step height was varied from 4×103 to 1.2×104. The reattachment length was obtained by a flow visualization technique, total pressure probe and shear velocity plots. Of all the three methods adopted the flow visualization method is simpler and gives better results. Mean pressures were found to be strongly dependent on perforation level of the normal plate. The shape and size of the bubble gets reduced both in height and length up to 30% perforation level. For higher perforation of the normal plate the bubble is completely swept out.