Three-dimensional phase-field modeling of the drop impact on a solid superhydrophobic flat surface

The three-dimensional water drop impact onto a solid superhydrophobic surface is numerically investigated via the diffuse interface method. In the present work, a laminar multiphase flow module is developed based on the phase-field approach as a part of the open-source, multiphysics simulation environment MOOSE. The fully-coupled, implicit-in-time framework relies on the continuous Galerkin finite element discretization of the Cahn-Hilliard Navier-Stokes equations with SUPG/PSPG stabilization technique for the fluid flow, which allows using linear finite elements for pressure and velocity at high Reynolds numbers. To prevent the unphysical droplet mass loss, a Lagrange multiplier has been introduced which globally conserves the order parameter on the entire computational domain. The effectiveness of the multiplier is demonstrated by locally conserving the phase area/volume and obtaining accurate physical results in drop oscillation and capillary jet breakup benchmark problems. Taking advantage of the Lagrange multiplier and adaptive mesh refinement at the interface, the normal drop impact onto a superhydrophobic flat surface is simulated and the results are in acceptable agreement with the experimental data and other numerical predictions.