Modification of Hindrance Factor due to the Presence of Charged Surface Heterogeneity

Presence of wall at the vicinity of a moving particle through a flowing or stationary fluid hindered the motion of the particle by implying more drag on it. Presence of charge on the particle alone or on both the wall and particle hinders the motion more due to electrokinetic effect like relaxation and EDL overlap. Presence of charged surface heterogeneity make the scenario worse. A 3D finite element model consisting of Navier-Stokes, Poisson and Nernst-Planck equation has been developed to study the effect of charged surface heterogeneity on the hindrance factor for a charged particle moving along the centerline of a cylindrical channel. It has been found out that presence of charge on the particle increase hindrance factor throughout the whole channel but presence of surface heterogeneity increase the factor at its vicinity only. Effect of solution concentration and separation gap between particle and flagellum are also investigated. Keywords— Debye length, Drag force, Hindrance factor, Relaxation, Surface heterogeneity