Open Access

ARTICLE

Determination of Non-Equilibrium Surface Tension Gradients in Marangoni Thermal Flows: Application to Aqueous Solutions of Fatty Alcohols

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1 Université Libre de Bruxelles, Service de Chimie Physique EP, CP 165-62, 50 Av. Roosevelt, 1050 Bruxelles, Belgium
2 LMSGC, UMR 113 (CNRS-ENPC-LCPC), 2 Allée Kepler 7742A0 Champs sur Marnes, France

Fluid Dynamics & Materials Processing 2008, 4(1), 1-10. https://doi.org/10.3970/fdmp.2008.004.001

Abstract

This study illustrates a relevant and practical method to determine the effective surface tension gradient in a layer subjected to a lateral temperature difference. In general, this can be hardly performed in situ without perturbing the flow. For this reason we rely on an indirect determination approach. A simple model is developed that relates the surface tension gradient to other quantities that can be measured without introducing significant disturbances in the system. Measurements of these quantities are performed in a set-up where the flow corresponds with a good approximation to a one-dimensional model. A previously used set-up has been upgraded for such a scope. The observations have been performed in fatty alcohol solutions. The results show that the surface tension gradients responsible for the onset of flow are not equilibrium ones.

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