Explicit numerical simulation of binary drop collision in a linear shear field at finite Reynolds numbers

Abstract

We use immiscible lattice-gas automata to study the collision of two drops in a linear shear field for a range of Reynolds number, Re, and Capillary number, Ca, at a single fixed viscosity ratio and impact parameter. We observe the full range of collision scenarios – coalescence in the compressional and extensional quadrants, ‘kiss-andbreak’, where the drops coalesce in the extensional quadrant before breaking up into two or more drops, and non-coalescence – depending on Re and Ca. Limited results suggest that the regions of the Re-Ca space associated with these collision scenarios are not separated by distinct boundaries but, rather, transition zones in which the probabilities of the two outcomes vary in a complementary fashion from one to the other.