Simulations in which the system of interest is mimicked are termed explicit numerical simulations (ENS). Direct numerical simulation (DNS) of turbulence is a well known example of ENS. Such simulations provide a basis for elucidating fundamentals in a way that is impossible experimentally, and formulating and parameterizing engineering models with reduced experimentation.

In this presentation, we will report an immiscible lattice-gas automata based study of the collision of two initially spherical drops suspended in a second liquid subject to a one-dimensional linear shear field. Capillary numbers ranging from Ca = 0.06 to Ca = 0.8 were investigated for the Reynolds numbers Re = 5/2ⁿ for n = 0 to 4. A range of collision scenarios are observed ranging from coalescence in the compressional and extensional quadrants both with and without secondary drop formation, to collisions we term ‘kiss-and-break’ in which the drops coalesce before separating again to form two or more drops, and non-coalescence. Limited results suggest that the regions of the parameter space associated with these various 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. The critical Capillary number is a strong function of the Reynolds number up to Re = 1.25 where it becomes largely independent of the Reynolds number.