A practical numerical framework for free surface flows based on CLSVOF method, multi-moment methods and density-scaled CSF model: Numerical simulations of droplet splashing

We propose a practical numerical framework for free surface flows with surface tension force. The numerical framework consists of the CLSVOF (coupled level set and volumeof-fluid) method, the THINC/WLIC (tangent of hyperbola for interface capturing/weighted line interface calculation) scheme, multi-moment methods (CIP-CSL and VSIAM3) and the density-scaled CSF (continuum surface force) model. We also propose an efficient implementation algorithms of the density-scaled CSF model and a curvature interpolation technique, based on the level set method. The framework is validated through three benchmark problems (equilibrium drop, Rayleigh-Taylor instability and single bubble rising) and comparisons with an experiment of droplet splashing. The numerical framework can well capture free surface flows with complex interface geometries like droplet splashing. The proposed surface force algorithms, especially the level set based curvature interpolation technique, play a key role in numerical simulations of free surface flows with complex interface geometries.