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The effect of an insoluble surfactant on the skin friction of a bubble

Li, J (2006) The effect of an insoluble surfactant on the skin friction of a bubble. European Journal of Mechanics, B/Fluids, 25. pp. 59-73. ISSN 0997-7546

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Abstract

In this paper, we develop a novel moving mesh method suitable for solving axisymmetric free-boundary problems, including the Marangoni effect induced by surfactant or temperature variation. This method employs a body-fitted grid system where the gas-liquid interface is one line of the grid system. We model the surfactant equation of state with a non-linear Langmuir law, and, for simplicity, we limit ourselves to the situation of an insoluble surfactant. We solve complicated dynamic boundary conditions accurately on the gas-liquid interface in the framework of finite-volume methods. Our method is used to study the effect of a surfactant on the skin friction of a bubble in a uniaxial flow. For the limiting case where the surface diffusivity is zero, the effect of a tangential stress generated by the surface tension gradient, allows us to explain a new phenomenon in high concentration regimes: larger surface tension, but also larger deformation. Furthermore, this condition leads to the formation of boundary layers and flow separation at high Reynolds numbers. The influence of these complex flow patterns is examined. © 2005 Elsevier SAS. All rights reserved.

Item Type: Article
Uncontrolled Keywords: Flow separation Free-surface problem Interface tracking Langmuir state equation Marangoni effect Moving mesh method Skin friction Surfactant
Subjects: UNSPECIFIED
Divisions: Div A > Fluid Mechanics
Depositing User: Cron Job
Date Deposited: 07 Mar 2014 11:21
Last Modified: 26 Nov 2014 19:06
DOI: 10.1016/j.euromechflu.2005.04.002