Particle dynamics at fluid interface by pseudo-potential lattice Boltzmann method coupled with smoothed profile method

Fluid–solid coupling widely exists in some natural phenomena and industrial applications. However, it is still an important challenge to correctly capture the transient changes of particles at fluid interface. We develop a lattice Boltzmann model for particle dynamics at fluid interface, which adopts a coupling strategy by combining the pseudo-force (Shan-Chen) multiphase multicomponent model and the smoothed profile method. In the coupling strategy, a novel extrapolation boundary condition is applied for fluid–solid interface, a repulsive force (bounce-back force) between solid node and fluid node is introduced in the coexistence region (at the fluid–solid interface), to form the interaction between fluid and solid particle. Thanks to the proposed fluid–solid coupling method, the drag force on solid particles can be correctly described, especially for situations of high solid volume fractions. It is found that the wetting angle θ between fluid interface and particle surface is basically linear with the repulsive force coefficient difference ΔG. What is more, to further validate the reliability of our proposed model, we performed two groups of simulations for different Bos = 0.51 (0.84) and 0.83 (1.35), they are the single particle trapped under gravity at deformed fluid interface and the falling single particle impacts fluid interface in the presence of gravity, respectively, and good agreements between simulation results and experimental ones in the description of the relationship between the inertial force and the interfacial tension are obtained, and their correlations are both close to 1, which proves the reliability of our proposed model.