# Fully developed and transient concentration profiles of particulate suspensions sheared in a cylindrical Couette

## TL;DR

This study experimentally examines particle migration in non-Brownian suspensions within a Taylor-Couette setup, validating the suspension balance model for concentration profiles and identifying its limitations through detailed measurements.

## Contribution

It provides systematic measurements of concentration profiles, migration strain scale, and amplitude, and assesses the suspension balance model's accuracy in a wide-gap Taylor-Couette flow.

## Key findings

- Suspension balance model accurately predicts concentration profiles for bulk volume fractions 20-50%.
- Measured migration strain scale and amplitude highlight the model's limits.
- Experimental data supports the model's applicability in non-Brownian shear flows.

## Abstract

We experimentally investigate particle migration in a non-Brownian suspension sheared in a Taylor-Couette configuration and in the limit of vanishing Reynolds number. Highly resolved index-matching techniques are used to measure the local particulate volume fraction. In this wide-gap Taylor-Couette configuration, we find that for a large range of bulk volume fraction, $\phi_b \in [20\% - 50\%]$, the fully developed concentration profiles are well predicted by the suspension balance model of Nott \& Brady (J. Fluid Mech., vol. 275, 1994, pp. 157-199). Moreover, we provide systematic measurements of the migration strain scale and of the migration amplitude which highlight the limits of the suspension balance model predictions.