  The boundary treatment is fundamental for modeling fluid flows; especially,
in the lattice Boltzmann method, the curved boundary conditions effectively
improve the accuracy of single-phase simulations with complex-geometry
boundaries. However, the conventional curved boundary conditions usually cause
dramatic mass leakage or increase when they are directly used for multiphase
flow simulations. We find that the principal reason is the absence of nonideal
effect in the curved boundary conditions, followed by the calculation error. In
this paper, incorporating the nonideal effect into the linear interpolation
scheme and compensating for the interpolating error, we propose a multiphase
curved boundary condition to treat the wetting boundaries with complex
geometries. A series of static and dynamic multiphase simulations with large
density ratio verify that the present scheme is accurate and ensures mass
conservation.
