Efficient simulation of non-crossing fibers and chains in a hydrodynamic solvent

TL;DR

This paper introduces an efficient simulation method for Brownian fiber suspensions that accounts for fiber uncrossability and hydrodynamic interactions, enabling detailed studies of fiber dynamics in viscous environments.

Contribution

The paper presents a novel simulation approach that conserves hydrodynamics and incorporates fiber uncrossability, applicable to semiflexible fibers in viscous solvents.

Findings

Hydrodynamic interactions have a small but observable effect on fiber behavior.

The non-crossing constraint significantly hinders fiber displacement, matching theoretical predictions.

The method facilitates future studies of microrheology and active probe responses in fiber suspensions.

Abstract

An efficient simulation method is presented for Brownian fiber suspensions, which includes both uncrossability of the fibers and hydrodynamic interactions between the fibers mediated by a mesoscopic solvent. To conserve hydrodynamics, collisions between the fibers are treated such that momentum and energy are conserved locally. The choice of simulation parameters is rationalised on the basis of dimensionless numbers expressing the relative strength of different physical processes. The method is applied to suspensions of semiflexible fibers with a contour length equal to the persistence length, and a mesh size to contour length ratio ranging from 0.055 to 0.32. For such fibers the effects of hydrodynamic interactions are observable, but relatively small. The non-crossing constraint, on the other hand, is very important and leads to hindered displacements of the fibers, with an effective tube diameter in agreement with recent theoretical predictions. The simulation technique opens the way to study the effect of viscous effects and hydrodynamic interactions in microrheology experiments where the response of an actively driven probe bead in a fiber suspension is measured.