Resistance functions for two unequal spheres in linear flow at low Reynolds number with the Navier slip boundary condition

Abstract

Resistance functions for two spherical particles with the Navier slip boundary condition in general linear flows, including rigid translation, rigid rotation, and strain, at low Reynolds number are derived by the method of reflections as well as twin multipole expansions. In the solutions, particle radii and slip lengths can be chosen independently. In the course of calculations, single-sphere problem with the slip boundary condition is solved by Lamb's general solution and the expression of multipole expansions, and Fax\'{e}n's laws of force, torque, and stresslet for slip particle are also derived. The solutions of two-body problem are confirmed to recover the existing results in the no-slip limit and for the case of equal scaled slip lengths.