Multi-Sink Solutions to the Self-Similar Euler Equations

Abstract

We construct examples and provide a classification of self-similar solutions to the two-dimensional incompressible Euler equations whose pseudo-velocity fields possess more than one stagnation point. These solutions are also homogeneous steady states of the Euler equations. In contrast, we prove that any homogeneous self-similar solution with bounded vorticity away from the origin necessarily admits only a single stagnation point, located at the origin. The solutions we construct develop velocity cusps along rays from the origin, and this allows for additional stagnation points of the pseudo-velocity field.

23 pages, 4 figures, 1 table. We added a proof of existence of multi-sink solutions and a classification of homogeneous self-similar solutions obtained by gluing