Rheological properties of soft-glassy flows from hydro-kinetic simulations

TL;DR

This study uses lattice kinetic simulations to analyze the rheological behavior of soft-glassy materials under different flow conditions, revealing a consistent Herschel-Bulkley relation and the importance of non-local stress relaxation.

Contribution

It introduces a comprehensive numerical analysis of soft-glassy flows under various loads, demonstrating the universality of the Herschel-Bulkley rheology and the role of cooperativity in non-local stress relaxation.

Findings

Rheology follows Herschel-Bulkley law across conditions

Yield stress is largely independent of loading scenario

Rescaling parameters captures heterogeneous flow behavior

Abstract

Based on numerical simulations of a lattice kinetic model for soft-glassy materials, we characterize the global rheology of a dense emulsion-like system, under three representative load conditions: Couette flow, time-oscillating Strain and Kolmogorov flow. It is found that in all cases the rheology is described by a Herschel-Bulkley (HB) relation, $\sigma = {\sigma}_{Y} + A S^{\beta}$, with the yield stress ${\sigma}_{Y}$ largely independent of the loading scenario. A proper rescaling of the HB parameters permits to describe heterogeneous flows with space-dependent stresses, based on the notion of cooperativity, as recently proposed to characterize the degree of non-locality of stress relaxation phenomena in soft-glassy materials.