Simulating hydrodynamic interactions in colloidal suspensions using multiparticle collision dynamics with rigid-body constraints

TL;DR

This paper introduces a rigid-body multiparticle collision dynamics method for simulating colloidal suspensions, offering improved efficiency and compatibility with complex particle shapes.

Contribution

The authors develop a rigid-body MPCD approach that reduces computational cost and allows larger timesteps compared to harmonic-bond models.

Findings

Rigid-body model reproduces expected particle statistics.

Achieves nearly tenfold speedup in simulations.

Compatible with complex-shaped colloidal particles.

Abstract

We develop a method for simulating colloidal suspensions using multiparticle collision dynamics (MPCD) with a discrete particle model represented as a rigid body. The key steps for incorporating the rigid-body constraints are to thermalize the velocities of the discrete sites before they participate in the MPCD collision step, then transfer momentum from the sites to the rigid body. We demonstrate that the rigid-body model produces the expected statistics for a single spherical particle and the same transport properties for a hard-sphere colloidal suspension as an equivalent model using harmonic bonds to maintain the site geometry. Importantly, the rigid-body model has less computational overhead and permits a larger simulation timestep than the harmonic-bond model, leading to a nearly order of magnitude speedup in benchmark simulations of hard-sphere colloidal suspensions. Our method is compatible with arbitrary discretization, so it enables more efficient MPCD simulations of suspensions of colloidal particles with complex shapes.