An improved curved boundary scheme for pseudopotential lattice Boltzmann method with different wettability

The lattice Boltzmann method (LBM) has a natural advantage in dealing with complex solid boundaries. However, it proves to be challenging in LBM to deal with contact angles in an intricate curved surface for multiphase flows. Applying traditional curved boundary schemes could produce relatively accurate results near complex geometric boundaries, but they often lead to issues such as mass leakage. As a result, in the current study, two improved curved boundary schemes are proposed to cope with flow problems with intricate geometric boundaries by introducing non-ideal force into the linear interpolation scheme and the Zhao–Yong scheme, followed by mass compensation for interpolation errors. The accuracy and mass conservation of the two proposed boundary schemes have been thoroughly validated through a series of numerical tests involving static droplet and dynamic multiphase flow. Meanwhile, the two curved schemes with central linear interpolation and multireflection schemes are also utilized to successfully achieve the different wettability of curved walls. It is found that mass correction and non-ideal force are not required for such schemes when simulating the wetting phenomenon of triple-point contact angles at curves. In addition, the accuracy of simulations is affected by different wettability schemes, and therefore, the contact angles for various wall wettability models have also been investigated in the present study. It is demonstrated that the improved virtual-density scheme does not result in unphysical layers and has smaller spurious currents as well. These advantages do not occur in other schemes, such as fluid–solid interaction, improved fluid–solid interaction, and virtual-density schemes.