On The Problem of Falling Motion of a Circular Cylinder and a Vortex Pair in a Perfect Fluid¹

Abstract—We consider a system consisting of a heavy circular cylinder in the field of gravity interacting dynamically with a vortex pair in a perfect fluid. The circulation about the cylinder is assumed to be zero. It is shown that, unlike the famous Föppl configuration, the vortices cannot be in a relative equilibrium. An asymptotic system and a suitable regularization are considered.