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Contact and Stress Anisotropies in Start Up Flows of Collodial Suspensions

Published

Author(s)

Nicos Martys, William L. George, Didier Lootens, Pascal Hebraud

Abstract

Spatio-temporal correlations in start-up flows of attractive colloids are explored by numerical simulations. The suspension is first allowed to flocculate during a time tw, then the stress necessary to induce its flow is computed. Whereas at low volume fractions, the stress is a universal function of the deformation, at high volume fractions, scaling behavior is no longer observed and an excess of stress becomes necessary at low shear. The onset of flow is dominated by the creation of contacts between the particles at low shear rates, and by their disruption at high shear rates. Under flow, the contacts between colloids become strongly anisotropic. The excess of stress occurs when the contacts are oriented in the compression gradient of the shear flow.
Citation
Physical Review E (Statistical, Nonlinear, and Soft Matter Physics)
Volume
50
Issue
3

Keywords

Suspensions, colloids, dissipative particle dynamics, yield stress, rheology

Citation

Martys, N. , George, W. , Lootens, D. and Hebraud, P. (2009), Contact and Stress Anisotropies in Start Up Flows of Collodial Suspensions, Physical Review E (Statistical, Nonlinear, and Soft Matter Physics) (Accessed July 27, 2021)
Created September 11, 2009, Updated February 19, 2017