Issue 8, 2024

Cross-streamline migration and near-wall depletion of elastic fibers in micro-channel flows

Abstract

The complex dynamics of elastic fibers in viscous fluids are central to many biological and industrial systems. Fluid–structure interactions underlying these dynamics govern the shape and transport of flexible fibers, and understanding these interactions can help tune flow properties in applications such as microfluidic separation, printing and clogging. In this work, we use slender-body theory to study micromechanical dynamics that arise from the coupling between the elastic backbone of a fiber and the local straining flow that contributes to filament flipping and cross-streamline migration. The resulting transverse drift is unbiased in either direction in simple shear flow. However, a non-uniform shear rate results in bias towards regions of high shear, which we connect to the shape transitions during flips. We discover a depletion layer that forms near the boundaries of pressure-driven channel flow due to the competition between such a cross-streamline drift and steric exclusion from the walls. Finally, we develop scaling laws for the curvature of filaments during flip events, demonstrating the origin of the drift bias in non-uniform flows, and confirm this behavior from our simulations. Put together, these results shed light on the role of a local and dominant coupling between elasticity and viscous resistance in dictating long-term dynamics and transport of elastic fibers in confined flows.

Graphical abstract: Cross-streamline migration and near-wall depletion of elastic fibers in micro-channel flows

Supplementary files

Article information

Article type
Paper
Submitted
06 Nov 2023
Accepted
23 Jan 2024
First published
26 Jan 2024

Soft Matter, 2024,20, 1725-1735

Cross-streamline migration and near-wall depletion of elastic fibers in micro-channel flows

T. Nguyen and H. Manikantan, Soft Matter, 2024, 20, 1725 DOI: 10.1039/D3SM01499A

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements