Fluctuating Lift Forces of the Karman Vortex Streets on Single Circular Cylinders and in Tube Bundles: Part 2—Lift Forces of Single Cylinders

Abstract

The fluctuating lift force of the Karman vortex on a single circular cylinder will be investigated theoretically for an ideal inviscid vortex street with rectilinear vortices. In this investigation the model introduced by von Karman will be used. As a result, the relationship between the fluctuating lift coefficient CL and the characteristic dimensions of the vortex street can be derived. This leads to establishing the equation between the fluctuating lift coefficient CL and the steady pressure drag coefficient CD . Since the curve of the theoretical lift coefficient practically envelops the spreading field of the experimentally determined points, the theory can be considered to be adequate to give the right order of magnitude for the lift of the Karman vortex. It will further be shown, that the spread of the measured values is in connection with the correlation length of the vortex along the cylinder axis.