Influence of surfactant solubility on the deformation and breakup of a bubble or capillary jet in a viscous fluid

Y.-N. Young, M. R. Booty, M. Siegel, J. Li
2009 Physics of Fluids  
In a previous study ͓M. Hameed et al., J. Fluid Mech. 594, 307 ͑2008͔͒ the authors investigated the influence of insoluble surfactant on the evolution of a stretched, inviscid bubble surrounded by a viscous fluid via direct numerical simulation of the Navier-Stokes equations, and showed that the presence of surfactant can cause the bubble to contract and form a quasisteady slender thread connecting parent bubbles, instead of proceeding directly toward pinch-off as occurs for a surfactant-free
more » ... a surfactant-free bubble. Insoluble surfactant significantly retards pinch-off and the thread is stabilized by a balance between internal pressure and reduced capillary pressure due to a high concentration of surfactant that develops during the initial stage of contraction. In the present study we investigate the influence of surfactant solubility on thread formation. The adsorption-desorption kinetics for solubility is in the diffusion controlled regime. A long-wave model for the evolution of a capillary jet is also studied in the Stokes flow limit, and shows dynamics that are similar to those of the evolving bubble. With soluble surfactant, depending on parameter values, a slender thread forms but can pinch-off later due to exchange of surfactant between the interface and exterior bulk flow.
doi:10.1063/1.3176462 fatcat:aad2nfa4sjgyvigczevyuihkvm