Flow Characteristics around a Circular Cylinder with a Slit : 1st Report, Flow Control and Flow Patterns

Abstract

Experimental investigations on the flow characteristics around a circular cylinder with a slit have been carried out. Flow visualization, how-wire measurements of the wake flow and the distributions of the static pressure coefficients around the cylinder have been made. The experiments were car-ried out in the Reynolds number region of 13800 to 52000 for two slit ratios of s/d=0.080 and 0.185. Three different typical flow patterns were found for the inclination of the slit β. For 0°≤β≤40°, the self-injection into the wake was observed. In this case, the base pressure rose and vortex formation region moved downstream. For 40°<β<60°, the effect of the slit was little. For 60°≤β≤90°, boundary layer suction was observed periodically with a period of the shed vortices. In this case, the base pressure coefficient dropped and the shedding frequency decreased.