Stability of restructured non-fractal aggregates in simple shear flow

Abstract

The restructuring behavior of non-fractal aggregates in simple shear flow is numerically investigated. The change in internal structure of aggregates having different packing properties is examined by Lagrangian simulation method. The many-body hydrodynamic interaction is rigorously estimated by Stokesian dynamics approach while the adhesion of aggregate is manifested via particle–particle interaction. The simulation results show that the restructuring of aggregate originates from the superimposition of rotational and extensional component of simple shear flow. The aggregate rearranges its particles so that a stable structure corresponding to the applied shear flow is obtained. The stable structure is considered as dynamic equilibrium resulting from the balance of the forming and the disintegrating of the bonds between particles. The stable structure of aggregate is dependent strongly on shear condition but weakly on initial structure of aggregate. Despite of the significant difference in the initial packing properties, the stable structure reveals only slightly different. The dependence of stable structure on high shear tress condition is similar for all aggregates. The difference in stable structure of aggregate at low shear stress arises from the irreversible behavior of particle from quasi-stable structure to static structure.