Hydrodynamics of multiple coalescence collisions of liquid drops: From the modelling of the coalescence phenomenon to flocculation of drops in 3d using the sph formalism

Abstract

In this chapter, we present three-dimensional numerical calculations of the collision and coalescence of multiple water drops of equal size in a vacuum environment, using a Lagrangian mesh-free scheme based on the Smoothed Particle Hydrodynamics (SPH) formalism. The water drops are modelled using a general Mie-Grüneisen equation of state. Attention is focused for collision velocities from low to moderate so that shattering separation is excluded. Depending on the collision velocity three different possible outcomes are predicted by the calculations: permanent coalescence, coalescence accompanied by fragmentation into a few satellite droplets, and flocculation of the drops with no coalescence.