Evaporation-induced saline Rayleigh convection inside a colloidal droplet
SCIE
SCOPUS
- Title
- Evaporation-induced saline Rayleigh convection inside a colloidal droplet
- Authors
- Kwan Hyoung Kang; Hee Chang Lim; Hee Woong Lee; Lee, SJ
- Date Issued
- 2013-04
- Publisher
- AMER INST PHYSICS
- Abstract
- Inside evaporating two-component sessile droplets, a family of the Rayleigh convection exists, driven by salinity gradient formed by evaporation of solvent and solute. In this work, the characteristic of the flow inside an axisymmetric droplet is investigated. A stretched coordinate system is employed to account for the effect of boundary movement. A scaling analysis shows that the flow velocity is proportional to the (salinity) Rayleigh number (Ra-s) at the small-Rayleigh-number limit. A numerical analysis for a hemispherical droplet exhibits the flow velocity is proportional to the non-dimensional number Ra-s(1/2), at high Rayleigh numbers. A self-similar condition is established for the concentration field irrespective of the Rayleigh numbers after a moderate time, and the flow field is invariant with time at this stage. The scaling relation for the high Rayleigh numbers is verified experimentally by using aqueous NaCl droplets. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4797497]
- URI
- https://oasis.postech.ac.kr/handle/2014.oak/12555
- DOI
- 10.1063/1.4797497
- ISSN
- 1070-6631
- Article Type
- Article
- Citation
- Physics of Fluids, vol. 25, no. 4, page. 42001, 2013-04
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