Numerical analysis of droplet impact onto liquid film

Normal impingement of a single droplet on a thin liquid film is investigated numerically solving the axisymmetric Navier-Stokes equations. Gravity and viscosity are taken into account whereas compressibility effects are neglected. Two phases are tracked by means of volume of fluid method and adaptive mesh refinement is used to increase accuracy of the interface. Numerical results are validated both qualitatively and quantitatively using experimental measurements. Effects of gas density, gas viscosity, and film thickness on the crown behavior are studied. Influence of droplet deviation from spherical shape on the crown behavior is investigated. It is shown that increasing the gas density leads to reduction of crown radius evolution rate, while gas viscosity does not affect the rate of crown radius evolution. Development rate of crown height decreases by increasing the gas density. Reynolds number and splashing regime can change the effect of gas viscosity on the crown height evolution. Deviation of droplet from sphere can change behavior of crown completely as result of change in droplet mass center position. Difference between numerical results and experimental ones is justified using different droplet shapes. (C) 2014 AIP Publishing LLC.