Modelling the Microstructure and Stress in Dense Suspensions Under Inhomogeneous Flow

TL;DR

This paper develops a tensor model incorporating shear rate fluctuations to understand the complex microstructure and stress behavior of dense suspensions under inhomogeneous flow, aligning well with particle simulations.

Contribution

It introduces a novel tensor model that accounts for shear rate fluctuations in dense suspensions under inhomogeneous flow conditions.

Findings

Model predicts regions with low macroscopic friction below yielding

Model captures volume fractions above jamming

Qualitative agreement with particle-based simulations

Abstract

Under inhomogeneous flow, dense suspensions exhibit complex behaviour that violates the conventional homogenous rheology. Specifically, one finds flowing regions with a macroscopic friction coefficient below the yielding criterion, and volume fraction above the jamming criterion. We demonstrate the underlying physics by incorporating shear rate fluctuations into a recently proposed tensor model for the microstructure and stress, and applying the model to an inhomogeneous flow problem. The model predictions agree qualitatively with particle-based simulations.