Two Computational Models for Simulating the Tumbling Motion of Elongated Particles in Fluids

TL;DR

This paper compares two computational models for simulating the tumbling motion of elongated particles in fluids, evaluating their accuracy, computational efficiency, and potential for extension in low Reynolds number regimes.

Contribution

It introduces a new 3D lattice Boltzmann method for fiber simulation and systematically compares it with the traditional slender body integral equation approach.

Findings

Both models accurately simulate fiber dynamics in fluids.

The lattice Boltzmann method offers higher computational efficiency on parallel supercomputers.

Each method has distinct advantages and limitations in accuracy and scalability.

Abstract

Suspensions with fiber-like particles in the low Reynolds number regime are modeled by two different approaches that both use a Lagrangian representation of individual particles. The first method is the well-established formulation based on Stokes flow that is formulated as integral equations. It uses a slender body approximation for the fibers to represent the interaction between them directly without explicitly computing the flow field. The second is a new technique using the 3D lattice Boltzmann method on parallel supercomputers. Here the flow computation is coupled to a computational model of the dynamics of rigid bodies using fluid-structure interaction techniques. Both methods can be applied to simulate fibers in fluid flow. They are carefully validated and compared against each other, exposing systematically their strengths and weaknesses regarding their accuracy, the computational cost, and possible model extensions.