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In this work, our recently developed weighted-orthogonal multiple-relaxation-time pseudopotential lattice Boltzmann (PLB) model [J. Tang et al., "Multiphase flow simulation with three-dimensional weighted-orthogonal multiple-relaxation-time pseudopotential lattice Boltzmann model," Phys. Fluids 33, 123305 (2021)] is further extended to simulate the complex wetting phenomenon on curved surfaces at large density ratios ( ρ l / ρ g ∼ 1000), where a new geometrical formulation scheme is proposed to characterize the wettability of the curved boundary. Compared with the existing geometrical formulation schemes, the significant advantage of the new scheme is that the characteristic vector representing the phase interface is no longer needed, and, thus, the complex calculations induced by the characteristic vector are avoided, which significantly simplifies computations and facilitates the implementation of the geometrical formulation scheme on curved boundaries. Meanwhile, it is applicable to both two-dimensional and three-dimensional (3D) simulations and maintains the feature of setting the contact angle explicitly. Furthermore, the numerical results of four classical wetting phenomenon benchmark cases at large density ratios predicted by the present model agree well with the analytical solutions, numerical results, or experimental results in the literature. It exhibits the capability of the present model coupled with the proposed scheme to simulate the wetting phenomenon involving curved surfaces with good numerical accuracy. Note that, to the author's knowledge, this is the first time that the geometrical formulation scheme has been successfully adopted in the 3D PLB model to simulate the wetting phenomenon on curved surfaces. We believe that this work lays the foundation for further application of the PLB model to the complex wetting phenomenon. [ABSTRACT FROM AUTHOR]

In this paper, based on two lattice models (D3Q19 and D3Q27), two three-dimensional weighted-orthogonal multiple-relaxation-time pseudopotential lattice Boltzmann (WMRT-PLB) models with tunable thermodynamic consistency and surface tension are developed in which the high-order terms of the equilibrium density distribution function and discrete forcing term in moment space are eliminated, and thus, the implementation of the collision process is simplified. The Chapman–Enskog analysis shows that the WMRT-PLB models can correctly recover the macroscopic Navier–Stokes equations in the low Mach number limit. Then, six classical multiphase flows benchmark cases are performed to validate the performance of the proposed model. The numerical results of the first three cases indicate that the developed WMRT-PLB models effectively weaken the non-physical coupling between kinetic viscosity and density, enhance the numerical stability because of the low spurious velocity, improve the computational efficiency by about 25% because of the simplification of the collision process, and increase the numerical accuracy in the dynamic problems. Meanwhile, the numerical results of the last three cases with the density ratio of 857.7 and the kinetic viscosity ratio of 1/15 agree well with the analytical solutions and experimental results reported in the literature. Note that it is also found that the simulation of droplet bouncing is still stable even when the Reynolds number is more than 3000, which shows the good numerical stability of the proposed model. It has the potential to be applied to the simulation of the complex multiphase flows with large density ratio and large Reynolds number. [ABSTRACT FROM AUTHOR]