Theoretical Studies of Flow-Induced Coalescence

Recent experimental studies of coalescence involving two equal size drops in a flow, both with and without a copolymer surfactant, have provided detailed data on the conditions for coalescence. This data presents a number of puzzles that are not explained by existing theoretical models of coalescence. In this presentation, we summarize our recent theoretical attempts to understand this data, via a combination of a small capillary number asymptotic theory for film drainage, exact boundary integral calculations of the two drop collision and coalescence process, and thin-film stability theory.