DROP FORMATION FROM A CAPILLARY TUBE IN THE PRESENCE OF SURFACTANT ¹⁾

In this study, the growth of an incompressible Newtonian drop from a vertical circular capillary tube in the presence of surfactant is analyzed. The flow is assumed to be axisymmetric and can be reduced to a spatially one-dimensional system by using the Taylor expansion and the lubrication approximation. The finite difference method combined with a coordinate transform is adopted for the numerical simulation. The results show that the existence of the surfactant will promote the breakup process of the drop, and prolong the limit length. Furthermore, the surfactant concentration has a more critical influence on the interface shapes than the surfactant activity.