Open Access

ARTICLE

Locomotion of a Viscous Drop, Induced by the Internal Secretion of Surfactant: Boundary Effects

by

1 Chemical Engineering Dept, Technion, Israel.

Fluid Dynamics & Materials Processing 2005, 1(2), 131-152. https://doi.org/10.3970/fdmp.2005.001.131

Abstract

We have studied the motion of a drop, induced by the internal secretion of a surface-active substance, in the vicinity of solid walls or non-deformable liquid-liquid interface under micro-gravity conditions. The secreted substance renders a non-uniform distribution of surfactant along the outer surface that, in turn, results in interfacial stress variation that ultimately leads to a surface motion and to locomotion of the drop. Cases of plane and spherical boundaries have been considered as well as cases of linear and non-linear dependence of the interfacial tension on concentration of surfactant. The dependence of the drop migration velocity on the location of the source and on the separation distance between the drop and the outer boundary as well as on the physical parameters of the system is reported. The dynamics of the drop is studied in the case of a fixed location of the source inside the drop, and in the case when it passively moves with the internal circulation.

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