An Immersed Boundary Method for Simulating CPEO-Driven Particle Kinematics

Electrokinetic flows can be used to drive novel phenomena in microscopic particle suspensions, opening new possibilities in soft materials, nanomedicine, and microrobotics. While models such as electrohydrodynamics (EHD) and concentration-polarization electroosmosis (CPEO) seek to explain these effects, the dominant mechanism controlling the kinematics of dielectric particle suspensions remains uncertain in many contexts. The CPEO model supposes that an applied electric field induces polarization in ionic concentrations at a particle's surface, and the movement of these ions results in a corresponding movement of the fluid in which the ions are suspended. Simulating the nonlinear PDEs governing electrokinetic flows has been restricted to single spherical particles under DC fields, since AC dynamics pose steep computational challenges. Here, I will introduce an efficient Immersed Boundary (IB) method that resolves these PDEs for time-varying fields, enabling rapid simulation of CPEO-driven moving bodies. I will also present validation cases for this new approach which compare against benchmark tests and experimental data.