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Title:	Influences of surfactant on the breakup of a fluid jet in viscous surrounding
Author:	Hameed, Muhammad Irfan
View Online:	njit-etd2005-069 (xi, 88 pages ~ 3.9 MB pdf)
Department:	Department of Mathematical Sciences
Degree:	Doctor of Philosophy
Program:	Mathematical Sciences
Document Type:	Dissertation
Advisory Committee:	Siegel, Michael (Committee chair) Papageorgiou, Demetrius T. (Committee member) Miura, Robert M. (Committee member) Booty, Michael R. (Committee member) Maldarelli, Charles M. (Committee member)
Date:	2005-05
Keywords:	Fluid jet Surfactant Viscous Slender Breakup Pinch-off
Availability:	Unrestricted
Abstract:	The effect of insoluble surfactant on the breakup of a fluid jet surrounded by another viscous fluid at low Reynolds number is studied both theoretically and experimentally. Equations governing the evolution of the interface and surfactant concentration are derived using a long wavelength approximation for the case of an inviscid jet and a slightly viscous jet surrounded by a more viscous fluid. These one dimensional partial differential equations governing the evolution of the slender jet are solved numerically for given initial interfacial perturbations and surfactant concentration. It is found that the presence of insoluble surfactant at the interface retards the pinch-off. The influence of surface diffusion of surfactant on the jet deformation is studied by varying surface Peclet number. It is found that greater diffusion of surfactant causes the jet to pinch faster. To check the predictions of our model, we performed experiments both for clean interface and as well as in presence of surfactants. The experimental results support the prediction of the theoretical model that the presence of surfactant slows down the pinch-off process. Results of the long wavelength model are also compared against the numerical simulations of the full problem. The solution of the full problem shows similar behavior to the simplified long wavelength model.