The stresslet for colloidal suspensions confined in a spherical cavity

Spherically-confined colloidal suspensions are a useful model system for representing a simple biological cell, where macromolecules interact and undergo diffusion, self-assembly, and flow. The microscopic forces between those colloids, including hydrodynamic, Brownian, and interparticle forces, are affected by confinement and thus computational models must represent these effects. In the Stokesian dynamics framework, the fluid-mediated interactions arising from these forces are represented by a hierarchy of hydrodynamic traction moments on particle surfaces. The initial Confined Stokesian dynamics algorithm^1,2 paved the way to such computational methods by obtaining the hydrodynamic force and torque in a spherical cavity but was restricted to equilibrium because the stresslet coupling is required to extract suspension viscosity and osmotic pressure. Here we present the exact solution for stresslet hydrodynamic functions of a colloid in a spherical cavity, and its application to more concentrated suspensions via the Confined Stokesian dynamics algorithm. With this algorithm, we predict high-frequency dynamic viscosities as well as osmotic pressure of confined Brownian suspensions.
[1]Aponte-Rivera and Zia, Phys Rev Fluids 2016 [2]Aponte-Rivera, Su, and Zia, J Fluid Mech 2018