Hybrid phase-field lattice Boltzmann method for two-phase flows

Accurate simulation of two-phase flows remains challenging due to the complex interfacial dynamics. The phase-field lattice Boltzmann method (PF-LBM) provides a powerful framework for such problems. However, conventional double-distribution-function models incur high memory costs, and finite-volume-based hybrid methods may suffer from grid-induced anisotropy. To address these limitations, a new hybrid PF-LBM is developed to improve isotropy and numerical accuracy for incompressible two-phase flows. In this approach, an improved finite volume method is employed to solve the conservative Allen–Cahn equation, where the flux formulation is reconstructed using the lattice Boltzmann (LB) mechanism to incorporate the effects across all discrete velocity directions. The hydrodynamics are solved using a velocity-based LB model equipped with a central-moment multiple-relaxation-time collision operator, enabling robust simulation of high-Reynolds-number flows. Numerical experiments demonstrate that the proposed hybrid scheme attains higher accuracy and improved fidelity in capturing complex interfacial deformations and topological transitions than the conventional finite-volume-based hybrid method.