Global axisymmetric solutions of 3D inhomogeneous incompressible Navier-Stokes Systems with nonzero swirl

TL;DR

This paper proves the global existence and decay properties of solutions to the 3D inhomogeneous incompressible axisymmetric Navier-Stokes equations with nonzero swirl under small initial data conditions.

Contribution

It establishes the global well-posedness and decay estimates for solutions with initial data satisfying specific smallness conditions, extending understanding of axisymmetric Navier-Stokes systems.

Findings

Global well-posedness under small initial data

Decay estimates for the swirl component

Conditions on initial data for existence and decay

Abstract

In this paper, we investigate the global well-posedness for the 3-D inhomogeneous incompressible Navier-Stokes system with the axisymmetric initial data. We prove the global well-posedness provided that $$\|\frac{a_{0}}{r}\|_{\infty} \textrm{ and } \|u_{0}^{\theta}\|_{3} \textrm{ are sufficiently small}. $$ Furthermore, if $\mathbf{u}_0\in L^1$ and $ru^\theta_0\in L^1\cap L^2$, we have \begin{equation*} \|u^{\theta}(t)\|_{2}^{2}+\langle t\rangle \|\nabla (u^{\theta}\mathbf{e}_{\theta})(t)\|_{2}^{2}+t\langle t\rangle(\|u_{t}^{\theta}(t)\|_{2}^{2}+\|\Delta(u^{\theta}\mathbf{e}_{\theta})(t)\|_{2}^{2}) \leq C \langle t\rangle^{-\frac{5}{2}},\ \forall\ t>0. \end{equation*}