Construction of the free-boundary 3D incompressible Euler flow under limited regularity
We consider the three-dimensional Euler equations in a domain with a free boundary with no surface tension. We construct unique local-in-time solutions in the Lagrangian setting for $u_0 \in H^{2.5+δ}$ such that the Rayleigh-Taylor condition holds and $\mathrm{curl}\,u_0 \in H^{2+δ}$ in an arbitrarily small neighborhood of the free boundary. We show that the result is optimal in the sense that $H^{3+δ}$ regularity of the Lagrangian deformation near the free boundary can be ensured if and only if initial vorticity has $H^{2+δ}$ regularity of vorticity near the free boundary.
math.AP↗