Level-set lattice Boltzmann method for interface-resolved simulations of immiscible two-phase flow.

A lattice Boltzmann (LB) scheme for a level-set equation is proposed to capture interface and is coupled with the LB model for incompressible fluid to simulate immiscible two-phase flows. The reinitialization of a level-set field is achieved directly by adding a source term to LB equation, which avoids solving an additional partial differential equation as required in traditional level-set methods. Compared to the classical phase-field lattice Boltzmann method, the proposed approach demonstrates significantly reduced errors in solving interface motion and deformation. Furthermore, GPU parallel computation is implemented for the level-set lattice Boltzmann method (LS-LBM) to enhance computational efficiency. To validate the LS-LBM, it is employed to simulate four benchmark problems: static droplet, layered Poiseuille flow, rising bubble, and Rayleigh-Taylor instability. Numerical results show that LS-LBM exhibits good stability, accuracy and high efficiency, demonstrating its feasibility for accurate simulations of immiscible two-phase flows, even with large density ratios or high Reynolds numbers.