Fluid Force Measurements for a Circular Cylinder with a Slit

Abstract

The drag and lift acting on a circular cylinder with a slit were measured in uniform flows. In subcritical Reynolds numbers, the fluid passing through the slit functions as a wake splitter plate which reduces the mean drag coefficient. The wake Strouhal number declines, and the fluctuating drag and lift decrease sharply. The slit is active for the suppression of the fluid force on the cylinder in a wide range of attack angles. A narrowed slit reduces the minimum drag coefficient, and a slight attack angle can suppress the fluctuating lift by stabilizing the flow behind the cylinder.