Adaptive near-contact repulsion in conservative Allen-Cahn phase-field lattice Boltzmann multiphase model

TL;DR

This paper introduces a local, adaptive near-contact repulsion mechanism in a phase-field lattice Boltzmann model to prevent artificial coalescence in multiphase flow simulations, improving accuracy and computational efficiency.

Contribution

It presents a novel, fully local repulsive flux that self-adjusts based on local film thickness, avoiding nonlocal geometric procedures and enhancing simulation robustness.

Findings

Effective suppression of artificial merging in multiphase flows

Robust near-contact dynamics in 3D bubble simulations

Maintains computational efficiency and parallelizability

Abstract

Unresolved thin-film dynamics often causes spurious coalescence in diffuse-interface simulations of multiphase flows. We address this issue by introducing a fully local repulsive near-contact flux in a conservative Allen--Cahn phase-field model coupled to lattice Boltzmann hydrodynamics. The interaction activates only for oppositely oriented nearby interfaces, with a strength that self-adjusts based upon an analytical estimate of the local film thickness extracted from the phase field. The resulting method circumvents nonlocal geometric procedures, preserves computational efficiency, and is well suited to massively parallel implementations. Tests on collision benchmarks and three-dimensional bubble swarms demonstrate robust suppression of artificial merging and physically consistent near-contact dynamics.