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Analytical solution for Stokes flow inside an evaporating sessile drop: Spherical and cylindrical cap shapes
Physics of Fluids (2009)
  • Hassan Masoud, State University of New York at Buffalo
  • James D. Felske, State University of New York at Buffalo
Abstract
Exact analytical solutions are derived for the Stokes flows within evaporating sessile drops of spherical and cylindrical cap shapes. The results are valid for all contact angles. Solutions are obtained for arbitrary evaporative flux distributions along the free surface as long as the flux is bounded at the contact line. Specific results and computations are presented for evaporation corresponding to uniform flux and to purely diffusive gas phase transport into an infinite ambient. Wetting and nonwetting contact angles are considered with the flow patterns in each case being illustrated. For the spherical cap with evaporation controlled by vapor phase diffusion, when the contact angle lies in the range 0≤θc<π/20≤θc<π/2, the mass flux of vapor becomes singular at the contact line. This condition requires modification when solving for the liquid-phase transport. Droplets in all of the above categories are considered for the following two cases: the contact lines are either pinned or free to move during evaporation. The present viscous flow behavior is compared to the inviscid flow behavior previously reported. It is seen that the streamlines for viscous flow lie farther from the substrate than the corresponding inviscid ones.
Disciplines
Publication Date
April, 2009
DOI
http://dx.doi.org/10.1063/1.3112002
Publisher Statement
© 2009 American Institute of Physics. Deposited here in compliance with publisher policies. Publisher's version of record: http://dx.doi.org/10.1063/1.3112002
Citation Information
Hassan Masoud and James D. Felske. "Analytical solution for Stokes flow inside an evaporating sessile drop: Spherical and cylindrical cap shapes" Physics of Fluids Vol. 21 Iss. 4 (2009) ISSN: 1070-6631
Available at: http://works.bepress.com/hassan-masoud/62/