Coalescing and break-up of viscous drops with surface tension through the Smoothed Particle Hydrodynamics

A study on the phenomena of drop coalescence and break-up is tackled for viscous flows with surface tension. The proposed analysis focuses on single-phase problems and is carried on by using the Smoothed Particle Hydrodynamics (SPH). This scheme allows for a straightforward treatment of the free surface and for an accurate description of the energy balance during the most delicate stages of coalescence and break-up. This latter aspect, combined with theoretical relations on the surface-tension energy, allowed for an in-depth characterization of the above phenomena in terms of energy evolution. A number of numerical test cases are considered in order to support and illustrate the main findings of the proposed work.