The action principle for generalized fluid motion including gyroviscosity

TL;DR

This paper develops a unified action principle framework for fluid motion models that incorporate gyroviscosity, ensuring energy conservation and broad applicability across various physical systems.

Contribution

It introduces a general set of energy-conserving fluid equations derived from an action principle, encompassing known models and including new insights into gyroviscous effects.

Findings

Derived a broad class of energy-conserving fluid equations including gyroviscosity.

Established model-independent conservation laws for energy and momentum.

Applied the formalism to systems with intrinsic angular momentum in diverse physics contexts.

Abstract

A general set of fluid equations that allow for energy-conserving momentum transport by gyroscopic motion of fluid elements is obtained. The equations are produced by a class of action principles that yield a large subset of the known fluid and magnetofluid models, including gyroviscosity. Analysis of the action principle yields broad, model-independent results regarding the conservation laws of energy and linear and angular momenta. The formalism is illustrated by studying fluid models with intrinsic angular momentum that may appear in the contexts of condensed matter, biological, and other areas of physics.