On the zero-radius limit of the motion of a rigid body in a perfect incompressible fluid


We will discuss the limit dynamics that one can obtain by considering the movement of a rigid solid in a perfect incompressible fluid, for a given initial data, as the size of the solid goes to zero. We obtain two limit dynamics in two different inertia regimes: in the case of a massive particle and in the case of a massless particle. In the first situation, we obtain in the limit a "massive" point vortex model, where a vortex point is accelerated by a force reminiscent of the Kutta-Joukowski force. In the second situation, we recover classical point vortex models.