Breadcrumb
Evaporating drops
Supervisor: Jens Eggers
Theme: Fluid Dynamics
If a drop of fluid is placed on a solid substrate, it frequently
spreads, if it "likes" the substrate material sufficiently.
However, if conditions are such that there is significant
evaporation, the dynamical behaviour of the drop changes radically.
Instead of spreading, the radius of the drop decreases and shrinks
to zero in finite time, with a characteristic scaling exponent of
close to 1/2. This has important consequences for applications: the rate
of evaporation from a substrate sprinkled with droplets is much
smaller than expected.
This project deals with the challenges of incorporating evaporation
into the drop dynamics, and its application to the shrinking
drop problem. To determine the evaporation, one has to solve
Laplace's equation in the exterior of the drop, which requires
global information from everywhere on the drop surface. In
addition, previous calculations have resulted in a rate of evaporation
which diverges at the edge of the drop.
We propose to take into account the gradual transition from
the drop profile to a thin film which is known to surround the
drop. This results in the evaporative singularity being regularised,
but now the dynamics of the drop and the evaporative problem are
coupled in a nonlocal fashion.
This project offers research and training in a variety of powerful
analytical techniques of matched asymptotic analysis, self-similarity,
and scaling. We are in close contact with experimental groups
investigating evaporating drops experimentally. This will
raise new questions and will stimulate interest.
Publications
-
Nonlocal description of evaporating drops (2010)
J. Eggers and L. M. Pismen
Phys. Fluids, vol: 22, Page: 112101
URL provided by the author -
Wetting and spreading (2009)
D. Bonn, J. Eggers, J. Indekeu, J. Meunier, E. Rolley
Rev. Mod. Phys., vol: 81, Pages: 739 - 805
URL provided by the author