Mesoscopic lattice Boltzmann modeling of soft-glassy systems: theory and simulations

TL;DR

This paper provides a theoretical analysis and simulation of a multi-component lattice Boltzmann model that captures the complex dynamics of soft-glassy materials, including relaxation, viscosity, and shear-thinning behaviors.

Contribution

It introduces a continuum free-energy framework for the lattice Boltzmann model and demonstrates its ability to reproduce key features of soft-glassy systems through simulations.

Findings

Model exhibits long-time relaxation and caging effects.

Shows shear-thinning flow above a critical shear.

Reproduces aging and structural arrest phenomena.

Abstract

A multi-component lattice Boltzmann model recently introduced (R. Benzi et al. Phys. Rev. Lett 102, 026002 (2009)) to describe some dynamical behaviors of soft-flowing materials is theoretically analyzed. Equilibrium and transport properties are derived within the framework of a continuum free-energy formulation, and checked against numerical simulations. Due to the competition between short-range inter-species repulsion and mid-range intra-species attraction, the model is shown to give rise to a very rich configurational dynamics of the density field, exhibiting numerous features of soft-flowing materials, such as long-time relaxation due to caging effects, enhanced viscosity and structural arrest, ageing under moderate shear and shear-thinning flow above a critical shear threshold.