Role of surfactant-induced Marangoni stresses in drop-interface coalescence

We study the effect of surfactants on dynamics a drop-interface coalescence using full three-dimensional direct numerical simulations. employ hybrid interface-tracking/level-set method, which takes into account Marangoni stresses that arise from surface-tension gradients, interfacial and bulk diffusion sorption kinetic effects. validate our predictions against experimental data Blanchette Bigioni ( Nat. Phys. , vol. 2, issue 4, 2006, pp. 254–257) perform parametric demonstrates delicate interplay between flow fields those associated with surfactant concentrations. The results this work unravel crucial role in physics coalescence, particular attention paid to their influence neck reopening terms stagnation-point inhibition, near-neck vorticity generation. demonstrate surfactant-laden cases feature rigidifying interface compared surfactant-free case, mechanism underpins observed surfactant-induced phenomena.