Simulation of drop impact on a thin liquid film by means of the VOF method

Numerical simulations of the early instants of a plane two-dimensional drop impact on a pre-existing thin film of the same liquid are performed. The evolution of the phenomenon is computed by solving the Navier-Stokes equations by means of a Volume of Fluid (VOF) method. The analysis takes into account viscous, inertial and surface tension forces; gravity is neglected. The surface tension forces are modeled by means of the Continuum Surface Force (CSF) model. Different incompressible regimes of motion are identified according to the values of Reynolds and Weber numbers. Spreading factor and pressure and velocity fields are investigated and the results are found to be in good agreement with previous numerical and experimental data. An analogy between plane and axisymmetric cases is also discussed.