The Lift Force Due to von Karman's Vortex Wake

Equations are developed which permit the estimation of the oscillating lift forces on bluff cylindrical bodies. The coefficient of lift is seen to be a function of the Strouhal number, the ratio of the lateral to longitudinal vortex spacing of the wake vortices and the ratio of the lateral vortex spacing to the width of the body. Introduction of certain, simplifying assumptions permit the determination of the lift coefficient of any bluff cylindrical body, provided the Strouhal number and the drag coefficient of that body at the Reynolds number of interest are known. The equations also predict an increase in the lift coefficient if the cylinder vibrates with a frequency less than the Strouhal frequency of the stationary cylinder and a decrease in lift coefficient if the cylinder vibrates at a higher frequency.