The global estimate for regular axially-symmetric solutions to the Navier Stokes equations coupled with the heat conduction

TL;DR

This paper derives a global a priori estimate for regular axially-symmetric solutions to the Navier-Stokes equations coupled with heat conduction in a bounded cylinder, facilitating proofs of global regularity.

Contribution

It provides the first global a priori estimate for such solutions, enabling potential extension and regularity results for the coupled Navier-Stokes and heat conduction system.

Findings

Global a priori estimate established for solutions

Reduction of nonlinearity aids in proving regularity

Extension of local solutions in time is possible under the estimate

Abstract

The axially-symmetric solutions to the Navier-Stokes equations coupled with the heat conduction are considered. in a bounded cylinder $\Omega \subset \mathbb{R}^3$. We assume that $v_r, v_{\varphi}, \omega_{\varphi}$ vanish on the lateral part $S_1$ of the boundary $\partial \Omega$ and $v_z, \omega_{\varphi}, \partial_z v_{\varphi}$ vanish on the top and bottom of the cylinder, where we used standard cylindrical coordinates and $\omega=\text{rot} v$ is the vorticity of the fluid. Moreover, vanishing of the heat flux through the boundary is imposed. Assuming existence of a sufficiently regular solution we derive a global a priori estimate in terms of data. The estimate is such that a global regular solutions can be proved. We prove the estimate because some reduction of nonlinearity are found.Moreover, deriving the global estimate for a local solution implies a possibility of its extension in time as long as the estimate holds.