Restructuring and Break-Up of Two-Dimensional Aggregates in Shear Flow

Vassileva, Nikolina D. and Ende van den, Dirk and Mugele, Frieder and Mellema, Jorrit (2006) Restructuring and Break-Up of Two-Dimensional Aggregates in Shear Flow. Langmuir, 22 (11). pp. 4959-4967. ISSN 0743-7463

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Abstract:	We consider single two-dimensional aggregates, containing glass particles, placed at a water/air interface. We have investigated the critical shear rate for break-up of aggregates with different sizes in a simple shear flow. All aggregates break-up nearly at the same shear rate (1.8 ± 0.2 s-1) independent of their size. The evolution of the aggregate structure before break-up was also investigated. With increasing shear rate, the aggregates adopt a more circular shape, and the particles order in a more dense, hexagonal structure. A simple theoretical model was developed to explain the experimentally observed break-up. In the model, the aggregate is considered as a solid circular disk that will break near its diameter. The capillary and drag force on the two parts of the aggregate were calculated, and from this force balance, the critical shear rate was found. The model shows a weak size dependence of the critical shear rate for the considered aggregates. This is consistent with the experimental observations.
Item Type:	Article
Copyright:	© 2006 American Chemical Society
Faculty:	Science and Technology (TNW)
Research Group:	Physics of Complex Fluids (PCF)
Research Institute:	Institute of Mechanics, Processes and Control-Twente (Impact)
Link to this item:	http://purl.utwente.nl/publications/59354
Official URL:	http://dx.doi.org/10.1021/la053460k
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