Marangoni circulation by UV light modulation on sessile drop for particle agglomeration
| Autor: | Tianyi Li, Aravinda Kar, Ranganathan Kumar |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Marangoni effect
Materials science Mechanical Engineering 02 engineering and technology Mechanics Stokes flow 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences 010305 fluids & plasmas Vortex Physics::Fluid Dynamics Light intensity Sessile drop technique Mechanics of Materials 0103 physical sciences Stream function Streamlines streaklines and pathlines 0210 nano-technology Particle deposition |
| Zdroj: | Journal of Fluid Mechanics. 873:72-88 |
| ISSN: | 1469-7645 0022-1120 |
| DOI: | 10.1017/jfm.2019.373 |
| Popis: | An analytical solution of a biharmonic equation is presented in axisymmetric toroidal coordinates for Stokes flow due to surface tension gradient on the free surface of sessile drops. The stream function profiles exhibit clockwise and counter-clockwise toroidal volumes. The ring or dot formed by the downward dividing streamlines between these volumes predicts the experimentally deposited particle ring or dot well. This finding suggests that the downward dividing streamline can be taken to be a reasonable indicator of where deposition occurs. Different light patterns directed at different locations of the droplet can give rise to a single spot or ring. A relationship between the positions of the light intensity peak and possible locations of particle deposition is analysed to demonstrate that the streamlines can be generated on-demand to achieve particle deposition at predetermined locations on the substrate. Toroidal corner vortices called Moffatt eddies have appeared in other corner flows and develop in this optical Marangoni flow as well near the contact line. |
| Databáze: | OpenAIRE |
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