Smooth interface compression: An improved algebraic vof method to model flows dominated by capillary forces

In volume-of-fluid methods, advection of the interface is subject to numerical diffusion, which has severe impact on the prediction of capillary forces. One approach are interface compression schemes, counteracting numerical diffusion by an artificial anti-diffusive flux. To eliminate numerical dependencies, e.g., the choice of the advection schemes or the strength of the anti-diffusive flux, a smooth interface compression (SMIC) scheme, is introduced, which limits interface compression to maintain a specific interface smoothness. The resulting less sharp interface preserves curvature information that would be lost by over-sharpening. The scheme is specifically designed for continuous surface stress formulations, and implemented in OpenFOAM on the basis of the interFoam solver. Validation and verification indicates slight drawbacks in the calculation of sharp interface advection but good results for a couple of steady-state and transient surface tension dominated test cases, including capillary waves, oscillating droplets, and wall-bounded flows.