Brownian rod-like particles suspension in non-homogeneous system: flow-microstructure coupling
Résumé
This study investigates the microstructure and rheological response of Brownian rod suspensions considering both spatial and orientational fluctuations in simple shear, Poiseuille and Couette flows. Focusing on rod-fluid interactions and concentration gradients, we account here for the effects of the rods concentration-orientation coupling. Numerical simulations, based on a kinetic macro-model previously derived [1], are used to analyze these results. In simple shear flow, the presence of the rods do not impact the flow, and translational diffusion does not modify the rheological properties of the suspensions. In Poiseuille flow, the rods cause a flattening of the velocity profile and the two-way coupling enhances the cross-streamlines migration toward the walls. The two-way coupling between the flow field and the rods control their orientation, migration behavior, and rheological properties. In Couette flow, rod-fluid coupling results in outward flow near the fixed cylinder. The translational diffusion plays a crucial role as higher translational Peclet numbers lead to pronounced migration of rods towards the channel walls and increased alignment in the flow direction. This coupling effect also affects the velocity profile in Couette flow. Our findings provide valuable insights into the complex behavior of suspended Brownian rods in different flow conditions.
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