Modeling of short-range interactions between both spherical and non-spherical rigid particles

We discuss computational methods to model collisions and lubrication at the particle scale in particle-laden flows. We review the well-established approaches to compute the Lagrangian tracking of spherical and non-spherical rigid particles with collisional and lubrication-dominated interactions. This should equip the readers with a variety of efficient methods to choose from depending on the specific features of the problem they are interested in. While non-spherical particle collisions and lubrication between a pair of spheres are (reasonably) well understood, much less is known about lubrication between two non-spherical particles. We also provide the readers with assorted ways to speed up the implementation of the collision (also referred to as granular dynamics) solver in a computer program. We put the numerical models to the test in simple and more challenging flow configurations. Finally, we summarize the challenges and open questions lying ahead to improve the modeling of short-range collisional and hydrodynamic particle–particle interactions in particle-laden flows.