Stable and contact-free time stepping for dense rigid particle suspensions
For researchers simulating dense suspensions, this work provides a more stable and efficient time-stepping method, though it is an incremental extension of existing work.
This paper extends a previous method for simulating dense rigid particle suspensions by treating all particle interactions implicitly, enabling larger time steps and smaller minimum separation distances. The method is validated on various flows and used to compute rheological properties.
We consider suspensions of rigid bodies in a two-dimensional viscous fluid. Even with high-fidelity numerical methods, unphysical contact between particles occurs because of spatial and temporal discretization errors. We apply the method of Lu et al. [Journal of Computational Physics, 347:160-182, 2017] where overlap is avoided by imposing a minimum separation distance. In its original form, the method discretizes interactions between different particles explicitly. Therefore, to avoid stiffness, a large minimum separation distance is used. In this paper, we extend the method of Lu et al. by treating all interactions implicitly. This new time stepping method is able to simulate dense suspensions with large time step sizes and a small minimum separation distance. The method is tested on various unbounded and bounded flows, and rheological properties of the resulting suspensions are computed.