Eur. Phys. J. E (2012) 35: 128
https://doi.org/10.1140/epje/i2012-12128-4

Regular Article

Restructuring of colloidal aggregates in shear flow

Coupling interparticle contact models with Stokesian dynamics

¹ Chair for Process Systems Engineering, Technische Universität München, Weihenstephaner Steig 23, 85350, Freising, Germany
² Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
³ Laboratoire de Physique des Solides, Université Paris-Sud, UMR 8502, 91405, Orsay, France

^* e-mail: setoryohei@me.com

Received: 25 April 2012
Revised: 26 September 2012
Accepted: 12 November 2012
Published online: 12 December 2012

Abstract

A method to couple interparticle contact models with Stokesian dynamics (SD) is introduced to simulate colloidal aggregates under flow conditions. The contact model mimics both the elastic and plastic behavior of the cohesive connections between particles within clusters. Owing to this, clusters can maintain their structures under low stress while restructuring or even breakage may occur under sufficiently high stress conditions. SD is an efficient method to deal with the long-ranged and many-body nature of hydrodynamic interactions for low Reynolds number flows. By using such a coupled model, the restructuring of colloidal aggregates under shear flows with stepwise increasing shear rates was studied. Irreversible compaction occurs due to the increase of hydrodynamic stress on clusters. Results show that the greater part of the fractal clusters are compacted to rod-shaped packed structures, while the others show isotropic compaction.