Regularity criteria via one directional derivative of the velocity in anisotropic Lebesgue spaces to the 3D Navier-Stokes equations

TL;DR

This paper establishes a new regularity criterion for the 3D Navier-Stokes equations based on the anisotropic Lebesgue space norms of the one directional derivative of velocity, involving a logarithmic integrability condition.

Contribution

It introduces a novel regularity criterion using anisotropic Lebesgue spaces for the derivative of velocity in 3D Navier-Stokes equations, expanding existing criteria.

Findings

Regularity of solutions is guaranteed under the new anisotropic criterion.

The criterion involves a logarithmic integrability condition on the derivative.

Conditions on p, q, r relate to classical regularity thresholds.

Abstract

In this paper, we consider the regularity criterion for 3D incompressible Navier-Stokes equations in terms of one directional derivative of the velocity in anisotropic Lebesgue spaces. More precisely, it is proved that u becomes a regular solution if the $\partial_3u$ satisfies $$\int^{T}_{0} \frac{\left\|\left\|\left\|\partial_3 u(t) \right\|_{L^p_{x_1}} \right\|_{L^q_{x_2}} \right\|^{\beta}_{L^{r}_{x_3}}} {1 + \ln\left(\|\partial_3u \left(t\right)\|_{L^2} + e\right)}dt < \infty,$$ $\text { where } \frac{2}{\beta}+\frac{1}{p}+\frac{1}{q}+\frac{1}{r}=1 \text { and } 2 < p, q, r \leq \infty, 1-\left(\frac{1}{p}+\frac{1}{q}+\frac{1}{r}\right) \geq 0 $.