Florian Janoschek
The dynamics of particles in non-dilute suspensions under flow are crucially determined by lubrication interactions. These interactions are of dissipative nature and diverge in magnitude whenever the gap between two particles becomes small. Simulation methods with finite resolution can resolve the hydrodynamics in the gap and the resulting stresses on the particles only insufficiently.
The approaches present in the literature to address this issue in lattice Boltzmann simulations can be grouped into two classes: Nguyen and Ladd (Phys. Rev. E, 66, 046708; 2002) focus on spherical particles and propose to explicitly apply the well-known singular terms in the two-particle resistance matrix to any pair of spheres that is near contact. Ding and Aidun (J. Stat. Phys. 112, 685; 2003) propose a method based on the interconnecting lattice links which, in principle, can be applied to particles of arbitrary shape provided that the local curvature is known.
This presentation will give a brief overview of the two approaches and their accuracy compared with the theoretically expected forces and couples on two spheres near contact. We developed an accurate and versatile method to account for normal and tangential lubrication interactions between aspherical particles. The main part of our contribution will consist of presenting this method, its efficient implementation, and its application to the lattice Boltzmann simulation of dense suspensions of prolate and oblate spheroids.