An extensible lattice Boltzmann method for viscoelastic flows: complex and moving boundaries in Oldroyd-B fluids

TL;DR

This paper introduces an extensible lattice Boltzmann method for simulating viscoelastic Oldroyd-B fluids with complex and moving boundaries, enabling advanced studies of biological and colloidal systems.

Contribution

The paper presents a novel lattice Boltzmann solver capable of handling complex geometries and moving boundaries in viscoelastic Oldroyd-B fluids, with validation and potential for broader applications.

Findings

Accurate simulation of rheological setups

Good agreement with literature on sedimenting colloids

Flexible extension to other constitutive equations

Abstract

Most biological fluids are viscoelastic, meaning that they have elastic properties in addition to the dissipative properties found in Newtonian fluids. Computational models can help us understand viscoelastic flow, but are often limited in how they deal with complex flow geometries and suspended particles. Here, we present a lattice Boltzmann solver for Oldroyd-B fluids that can handle arbitrarily-shaped fixed and moving boundary conditions, which makes it ideally suited for the simulation of confined colloidal suspensions. We validate our method using several standard rheological setups, and additionally study a single sedimenting colloid, also finding good agreement with literature. Our approach can readily be extended to constitutive equations other than Oldroyd-B. This flexibility and the handling of complex boundaries holds promise for the study of microswimmers in viscoelastic fluids.