# Microstructure and thickening of dense suspensions under extensional and shear flows

## TL;DR

This study uses numerical simulations to explore how microstructure influences the non-Newtonian rheological behavior of dense suspensions under extensional and shear flows, revealing flow-type dependence and normal stress differences.

## Contribution

It provides new insights into the microstructure-flow relationship and flow-type dependence in dense suspensions under different flow conditions.

## Key findings

- Flow-type dependence varies below and above thickening regimes.
- Normal stress differences are present regardless of flow-type dependence.
- Microstructure influences rheological properties significantly.

## Abstract

Dense suspensions are non-Newtonian fluids which exhibit strong shear thickening and normal stress differences. Using numerical simulation of extensional and shear flows, we investigate how rheological properties are determined by the microstructure which is built under flows and by the interactions between particles. By imposing extensional and shear flows, we can assess the degree of flow-type dependence in regimes below and above thickening. Even when the flow-type dependence is hindered, nondissipative responses, such as normal stress differences, are present and characterise the non-Newtonian behaviour of dense suspensions.