Publication detail

Constitutive Equations for Magnetic Active Liquids

FIALOVÁ, S. POCHYLÝ, F.

Original Title

Constitutive Equations for Magnetic Active Liquids

Type

journal article in Web of Science

Language

English

Original Abstract

This article is focused on the derivation of constitutive equations for magnetic liquids. The results can be used for both ferromagnetic and magnetorheological fluids after the introduced simplifications. The formulation of constitutive equations is based on two approaches. The intuitive approach is based on experimental experience of non-Newtonian fluids, which exhibit a generally non-linear dependence of mechanical stress on shear rate; this is consistent with experimental experience with magnetic liquids. In these general equations, it is necessary to determine the viscosity of a liquid as a function of magnetic induction; however, these equations only apply to the symmetric stress tensor and can only be used for an incompressible fluid. As a result of this limitation, in the next part of the work, this approach is extended by the asymmetry of the stress tensor, depending on the angular velocity tensor. All constitutive equations are formulated in Cartesian coordinates in 3D space. The second approach to determining constitutive equations is more general: it takes the basis of non-equilibrium thermodynamics and is based on the physical approach, using the definition of density of the entropy production. The production of entropy is expressed by irreversible thermodynamic flows, which are caused by the effect of generalized thermodynamic forces after disturbance of the thermodynamic equilibrium. The dependence between fluxes and forces determines the constitutive equations between stress tensors, depending on the strain rate tensor and the magnetization vector, which depends on the intensity of the magnetic field. Their interdependencies are described in this article on the basis of the Curie principle and on the Onsager conditions of symmetry.

Keywords

constitutive equations; magnetic liquid; ferromagnetic liquid; magnetorheological liquid; magnetic induction; viscosity; shear stress; shear rate

Authors

FIALOVÁ, S.; POCHYLÝ, F.

Released

11. 10. 2021

Publisher

MDPI

Location

BASEL

ISBN

2073-8994

Periodical

Symmetry

Year of study

13

Number

10

State

Swiss Confederation

Pages from

1910

Pages to

1910

Pages count

16

URL

https://www.mdpi.com/2073-8994/13/10/1910

Full text in the Digital Library

http://hdl.handle.net/11012/202256

BibTex

@article{BUT173078,
  author="Simona {Fialová} and František {Pochylý}",
  title="Constitutive Equations for Magnetic Active Liquids",
  journal="Symmetry",
  year="2021",
  volume="13",
  number="10",
  pages="1910--1910",
  doi="10.3390/sym13101910",
  issn="2073-8994",
  url="https://www.mdpi.com/2073-8994/13/10/1910"
}