Numerical simulations are performed for two rough spheres in nonlinear shear flow by the traction-corrected boundary element method with an added electrostatic-like force. It has been shown previously that the interaction of two rough spheres in nonlinear shear flow will result in a net permanent migration of the particle pair toward the low shear rate region of the flow field. In the current research, it is shown that a repulsive static force will augment the migration and that an attractive static force can diminish and even reverse the direction of migration. For oscillatory flows with an attractive static force between the spheres, the migration direction can change depending on the amplitude of the oscillation. (C) 2010 The Society of Rheology. [DOI: 10.1122/1.3429067]