Gagliardo-Nirenberg inequalities in Lorentz type spaces and energy equality for the Navier-Stokes system

TL;DR

This paper introduces new Gagliardo-Nirenberg inequalities in Lorentz spaces and provides improved criteria for energy conservation in the 3D Navier-Stokes equations, broadening the understanding of regularity and energy equality.

Contribution

It generalizes existing inequalities in Lorentz spaces and establishes novel energy conservation criteria for Navier-Stokes solutions, extending classical conditions.

Findings

New Gagliardo-Nirenberg inequalities in Lorentz spaces

Enhanced energy conservation criteria for Navier-Stokes equations

Improved conditions allowing Lorentz space norms in space-time

Abstract

In this paper, we derive some new Gagliardo-Nirenberg type inequalities in Lorentz type spaces without restrictions on the second index of Lorentz norms, which generalize almost all known corresponding results. Our proof mainly relies on the Bernstein inequalities in Lorentz spaces, the embedding relation among various Lorentz type spaces, and Littlewood-Paley decomposition techniques. In addition, we establish several novel criteria in terms of the velocity or the gradient of the velocity in Lorentz spaces for energy conservation of the 3D Navier-Stokes equations. Particularly, we improve the classical Shinbrot's condition for energy balance to allow both the space-time directions of the velocity to be in Lorentz spaces.