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Graduate Student-Faculty Seminars
Wednesday, October 19,
Cullimore Hall Room 611
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On Formation of
"Octopus-like" Structures in the Evolution of Droplets
Nebojsa Murisic
Department
of Mathematical Sciences
New
Jersey Institute of Technology
Abstract
This is a study of the influence of evaporation on the flow
within small drying droplets. In order to
explain recently discovered phenomena of the formation of octopus-like
structures on the edges of small evaporating droplets, we consider effects of Marangoni convection on stability of thin films. We begin
with the Navier-Stokes equations and introduce
boundary conditions at the liquid-gas interface which take into account
evaporation. We then proceed with simplifications of the model, including a
lubrication approximation. Finally, we
obtain single thin-film equation for the evolution of the droplet thickness.
Having identified that the effects of Marangoni
convection are destabilizing, we examine relevant physical and chemical
properties of water and isopropanol-2. We find that the role of Marangoni convection in destabilizing the thin film
(droplet) profile is more pronounced in droplets of volatile liquid (e.g.
isopropanol-2). We conclude with a description of future work.