A Lattice Boltzmann-Based Diffuse Interface Immersed-Boundary Scheme for Gas-Liquid-Solid Multiphase Flow

In this paper, we develop a lattice Boltzmann-based diffuse interface immersed-boundary scheme for gas-liquid-solid multiphase flows. Based on the conservative phase-field lattice Boltzmann method and the immersed boundary method (IBM), the fluid-particle interaction is modeled by a momentum exchange-based IBM for the flow field and a diffuse interface-based IBM with two layers of fictitious body-fitted Lagrangian grids for the phase field. We applied the method to simulate a series of cases of gas-liquid-solid multiphase flows including a squared cylinder standing still at gas-liquid interface, a circular cylinder standing still at gas-liquid interface, a light circular cylinder freely suspending at gas-liquid interface, two/three circular particle assembling at gas-liquid interface, and a number of circular particles randomly floating from liquid part to assembling at the gas-liquid interface. The proposed scheme can accurately characterize the mechanisms of dynamic wetting and interfacial interactions at the mesoscopic scale and has shown advantages in simulating complex gas-liquid-solid coupling problems.