The total force of interaction induced by a viscous binder between two equal-sized spheres had been previously analyzed. In this work, we extend the modeling approach to the interaction of dissimilar particles via a harmonic mean approximation used to compute the effective size of the interacting entities. We test the validity of this approximation to extrapolate these earlier analytical models to the practical processing scenario of particle size distributions generated during dispersive mixing. Additionally, we use an experimental methodology to simulate typical processing flow geometries and conditions ranging from the simple shear to dynamic shear to extensional flows. This enables application of the previously established algorithm, which is based on constant velocity interactions, to a range of realistic mixing modeling and simulation efforts. (c) Koninklijke Brill NV, Leiden and Society of Powder Technology, Japan, 2008.