Abstract
Experimental investigations have been made on the wake characteristics of groups of normal flat plates, consisting of two, three, or four plates placed side by side in a uniform flow with slits in between. When the ratio of the slit width to the plate width (slit ratio) was small, the gap flows were observed to be biassed either upward or downward in a stable way, leading to multiple, stable flow patterns for a single slit ratio value. Some regularities were found in the gap flow directions and the appearance of the flow patterns. The plate on the biassed side showed high drag and regular vortex shedding, while the plate on the unbiassed side showed the opposite. The variations with slit ratio of base pressure and STROUHAL number of individual plates showed similar tendencies when the neighboring gap flows were alike. In four-plate rows, the wake characteristics were compared with those of two dimensional perforated plates studied earlier by CASTRO.
