Multi-component lattice Boltzmann models for accurate simulation of flows with wide viscosity variation

TL;DR

This paper introduces multi-component lattice Boltzmann models capable of accurately simulating flows with extremely wide viscosity variations, maintaining simplicity and efficiency for engineering applications.

Contribution

The authors develop a new multi-component lattice Boltzmann model with boundary conditions that accurately handle complex geometries and high viscosity ratios, surpassing previous models in robustness and accuracy.

Findings

Accurately simulates flows with viscosity ratios up to 1000.

Maintains computational efficiency comparable to original models.

Validates robustness through comparison with analytical solutions and previous studies.

Abstract

Multi-component lattice Boltzmann models operating in a wide range of fluid viscosity values are developed and examined. The algorithm is constructed with the goal to enable engineering applications without sacrificing simplicity and computational efficiency present in the original Shan-Chen model and D3Q19 lattice scheme. Boundary conditions for modeling friction and wettability effects are developed for discrete representation of surfaces within a volumetric approach, which results in accurate flow simulation in complex geometry. Numerical validation of our models includes comparison to previous studies and analytical solutions. The results are shown to be robust and accurate up to an extremely small kinematic viscosity value of $0.0017$ lattice units and the extremely high ratio of components' kinematic viscosities of hundreds and up to a thousand. This improvement is significant compared to previous studies with Shan-Chen model \cite{2013_Yang,2004_Kang,2010_Dong}, in which reasonable accuracy was kept only at the viscosity ratio up to 10 in the Poiseuille flow and the fingering simulation.