Improbability of Collisions of Point-Vortices in Bounded Planar Domains

Abstract

In this paper, we prove that in bounded planar domains with $C^{2,\alpha}$ boundary, for almost every initial condition in the sense of the Lebesgue measure, the point-vortex system has a global solution, meaning that there is no collision between two point-vortices or with the boundary. This extends the work previously done in [C. Marchioro and M. Pulvirenti, Vortex Methods in Two-Dimensional Fluid Dynamics, Springer-Verlag, 1984] for the disk. The proof requires the construction of a regularized dynamics that approximates the real dynamics and some strong inequalities for the Green's function of the domain. The establishment of some useful estimates is discussed and the details of the proof are given in the original article [M. Donati, SIAM J. Math. Anal., 54 (2022), pp. 79--113].