Creeping transport of a spherical colloidal particle in concentric and eccentric micropolar porous media

Abstract

The slow, quasi-steady, axisymmetric translational motion of a solid spherical particle within an eccentric cavity containing a hydrogel medium is analyzed using a semi-analytical approach. The hydrogel is modeled as a porous medium saturated with a microstructured fluid exhibiting micropolar behavior. No-slip and no-spin conditions are applied at both the particle surface and the cavity wall. The hydrodynamic governing equations are solved by constructing general solutions from fundamental solutions formulated in two spherical coordinate systems—one centered on the particle and the other on the cavity. A collocation method is employed to satisfy the boundary conditions at the interfaces. The obtained results show strong agreement with existing literature. This study reveals that the cavity wall, micropolar fluid characteristics, and permeability parameters significantly influence the drag force acting on the particle. These findings provide valuable insights into controlled particle motion in hydrogel environments, with potential applications in targeted drug delivery and biomedical transport systems.