Experimental and numerical study of anomalous thermocapillary convection in liquid gallium

Janis Priede, Andreas Cramer, Andris Bojarevics, Alexander Yu Gelfgat, Pinhas Z. Bar-Yoseph, Alexander L. Yarin, Gunter Gerbeth

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13 Citations (Scopus)

Abstract

Thermocapillary Marangoni convection of liquid gallium was studied experimentally and numerically. A specially designed experimental setup ensured an oxide-free surface of the liquid gallium for a very long time. The convective flow at the free surface was found to be directed opposite to both buoyancy-driven and ordinary thermocapillary convection. The anomalous direction of the thermocapillary flow was explained by the presence of a small amount of a surface-active contaminant - lead adsorbed at the free surface. Two different approaches were used to describe the observed phenomenon. First, the flow was treated as a pure thermocapillary convection with a modified dependence of the surface tension on temperature so that to reproduce the measured velocity distribution. Second, a novel physical model was devised for the flow driven by the gradient of the surface tension induced by the temperature dependence of the concentration of the adsorbed layer of contaminant. In contrast to the ordinary thermocapillary convection in low-Prandtl-number liquids, there is a strong coupling between the flow and the driving force in the proposed model resulting in velocity profiles very similar to those observed in the experiment.

Original languageEnglish
Pages (from-to)3331-3339
Number of pages9
JournalPhysics of Fluids
Volume11
Issue number11
DOIs
Publication statusPublished - 1999 Nov

ASJC Scopus subject areas

  • Computational Mechanics
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering
  • Fluid Flow and Transfer Processes

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    Priede, J., Cramer, A., Bojarevics, A., Gelfgat, A. Y., Bar-Yoseph, P. Z., Yarin, A. L., & Gerbeth, G. (1999). Experimental and numerical study of anomalous thermocapillary convection in liquid gallium. Physics of Fluids, 11(11), 3331-3339. https://doi.org/10.1063/1.870192