Impulsively-Started Flow About Four Types of Bluff Body

Abstract

Measurement of the forces acting on a circular cylinder and those on three other noncircular cylinders is reported. The results confirm and quantify the profound effects of the shedding of the first two or three vortices on all the characteristics of resistance and demonstrate that the evolution of the flow, and hence the forces, significantly depend on whether the separation points are fixed or mobile, or a combination thereof. The data are expected to form the basis of future numerical analysis based on refined discrete vortex models.