Removing Type II singularities off the axis for the 3D axisymmetric Euler equations

TL;DR

This paper establishes a local blow-up criterion for smooth axisymmetric solutions to the 3D Euler equations, showing that certain vorticity conditions prevent singularity formation off the axis of symmetry.

Contribution

It introduces a new blow-up criterion based on vorticity integrability away from the axis, excluding singularities under specific growth conditions.

Findings

No singularity at $t=t_*$ if vorticity integral condition holds.

Singularity is excluded if vorticity grows slower than $(t_*-t)^{-2}$.

Results apply to regions away from the axis of symmetry.

Abstract

We prove local blow-up criterion for smooth axisymmetric solutions to the 3D incompressible Euler equation. If the vorticity satisfies $ \intl_{0}^{t_*} (t_*-t) \| \omega (t)\|_{ L^\infty(B(x_{ \ast}, R_0))} dt <+\infty$ for a ball $B(x_{ \ast}, R_0)$ away from the axis of symmetry, then there exists no singularity at $t=t_*$ in the torus $T(x_*, R)$ generated by rotation of the ball $B(x_{ \ast}, R_0)$ around the axis. This implies that possible singularity at $t=t_*$ in the torus $T(x_*, R)$ is excluded if the vorticity satisfies the blow-up rate $ \|\o (t)\|_{L^\infty (T(x_*, R))}= O\left(\frac{1}{(t_*-t)^\gamma}\right)$ as $t\to t_*$, where $\gamma <2$ and the torus $T(x_*, R)$ does not touch the axis.