English

The simplest microscopic model of a complex fluid: flow phenomena and constitutive relation

Soft Condensed Matter 2016-09-05 v1 Statistical Mechanics

Abstract

It was shown in [PRL 114, 138301 (2015)] that a remarkably simple dynamical model exhibits many of the complex flow regimes and non-equilibrium phase transitions characteristic of complex fluids. By removing extraneous detail, this simplest microscopic model of non-Newtonian flow can reveal the universal physics relevant to all complex fluids. Here we present more detailed results and a full derivation of the model's compact mean-field constitutive relation, with great potential scope for insights into universality and tractable mathematics. By enforcing local conservation of angular momentum, the one-dimensional (1D) XY-model (originally used for equilibrium magnetic systems) can be driven into various flow regimes, including simple Newtonian behaviour, shear banding, solid-liquid coexistence and slip-plane motion. The model demonstrates that the phenomenon of shear banding does not rely on details of tensorial stress fields, but can exist in 1D.

Keywords

Cite

@article{arxiv.1609.00560,
  title  = {The simplest microscopic model of a complex fluid: flow phenomena and constitutive relation},
  author = {R. M. L. Evans and Craig A. Hall and R. Aditi Simha and Tom Welsh},
  journal= {arXiv preprint arXiv:1609.00560},
  year   = {2016}
}

Comments

16 pages

R2 v1 2026-06-22T15:38:34.214Z