Electrostatic effects on resuspension of rigid-link fibers in turbulent flows

Fiber resuspension from smooth surfaces in a turbulent boundary layer flow including electrostatic effects is studied. A rigid-link fiber model which is composed of five rigidly attached ellipsoids is considered. The fiber contacts with the wall are modeled as spherical end joints. For an average of the Boltzmann charge distribution, as well as the saturation condition, the Coulomb, the image, the dielectrophoretic, and the polarization forces acting on the fiber in the presence of an imposed electric field are evaluated. The cases that charges are concentrated on the tip spherical joints, and when they are uniformly distributed along the ellipsoidal links are analyzed. The interfacial forces at the spherical contact points are determined by the Johnson–Kendall–Roberts (JKR) adhesion model. The theories of rolling and sliding detachment are used to study the onset of removal of fibers from surfaces in an air flow field. The hydrodynamic forces and torques acting on the fiber attached to a wall, along with the adhesion forces of contact nodes, are used in the model development. The minimum shear velocities needed to detach fibers of different sizes, orientations, and thickness from plane surfaces in the presence of an applied electric field are evaluated and discussed. It is shown, for saturation charge condition, the electric field strength significantly affects the critical velocity for removal of fibers from surfaces.