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Restructuring of colloidal aggregates in shear flow: coupling interparticle contact models with Stokesian dynamics
Ryohei Seto1, Robert Botet, Günter K Auernhammer
1Technische Universität München, Freising, Germany. setoryohei@me.com
The European Physical Journal. E, Soft Matter
|December 12, 2012
Summary
This study introduces a new method to simulate colloidal aggregates, revealing how they compact and change shape under increasing flow stress. The findings show fractal clusters restructure into rod-like or isotropic packed forms.
Area of Science:
- Colloid and Surface Science
- Computational Fluid Dynamics
- Materials Science
Background:
- Colloidal aggregates form complex structures under flow.
- Understanding their behavior is crucial for various applications.
- Existing simulation methods have limitations in capturing aggregate dynamics.
Purpose of the Study:
- To develop a coupled computational method for simulating colloidal aggregates.
- To investigate the structural evolution of aggregates under shear flow.
- To analyze the effects of hydrodynamic stress on aggregate morphology.
Main Methods:
- Coupling interparticle contact models with Stokesian dynamics (SD).
- Implementing contact models that mimic elastic and plastic particle behaviors.
- Simulating colloidal aggregates under stepwise increasing shear rates.
Main Results:
- Colloidal aggregates undergo irreversible compaction under increasing hydrodynamic stress.
- Fractal clusters predominantly restructure into rod-shaped packed structures.
- A portion of the aggregates exhibit isotropic compaction.
Conclusions:
- The coupled model accurately captures aggregate restructuring under flow.
- Hydrodynamic stress is a key factor driving aggregate compaction and shape change.
- The study provides insights into the mechanical behavior and morphology of colloidal aggregates.
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