Restructuring of colloidal aggregates in shear flows and limitations of the free-draining approximation

Volker Becker, Eva Schlauch, Marek Behr, Heiko Briesen

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75 Scopus citations

Abstract

We investigated the restructuring behavior of colloidal aggregates by means of the discrete element method. We used a recently proposed model [V. Becker, H. Briesen, Physical Review E 78 (6) (2008) 061404] for tangential inter-particle forces, capable of supporting bending moments. We extended this model by the capability of supporting torsional moments. The time evolution of the aggregates' radius of gyration was tracked and a power law relation between the number of primary particles and the final radius of gyration was found. For the hydrodynamic drag forces the free-draining approximation is employed. We investigated the quality of the free-draining approximation by fully resolved finite element simulations for small aggregates. We found that the free-draining approximation overestimates the drag forces and we identified the usage of effective shear rates as a possible ansatz for reduced modeling of hydrodynamic forces.

Original languageEnglish
Pages (from-to)362-372
Number of pages11
JournalJournal of Colloid and Interface Science
Volume339
Issue number2
DOIs
StatePublished - 15 Nov 2009

Keywords

  • Colloidal aggregates
  • DEM
  • FEM
  • Free-draining approximation
  • Tangential forces

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