MICHAEL MANGA: Recent Refereed Publications
Manga, M. and H.A. Stone (1995) Low Reynolds number motion
of bubbles, drops and
through fluid-fluid interfaces, Journal Fluid Mechanics, vol. 287,
The low Reynolds number buoyancy-driven translation of a deformable
drop towards and through a fluid-fluid interface
is studied using boundary integral calculations and
The Bond numbers characteristic of both the drop and the initially flat
fluid-fluid interface are sufficiently
large that the drop and interface become highly deformed, substantial
volumes of fluid may be entrained across the interface, and breakup of both
interfaces may occur.
Specifically, drops passing from a higher to lower viscosity fluid are extended
vertically as they pass through the interface.
For sufficiently large drop Bond numbers, the drop may deform continuously,
developing either an elongating tail or enlarging cavity
at the back of the drop,
analogous to the deformation characteristic of a single deformable drop
in an unbounded fluid.
The film of fluid between the drop and interface thins
most rapidly for those cases that
the drop enters a more viscous fluid or has a viscosity lower than the surrounding fluids.
In the laboratory experiments, bubbles
entering a less viscous fluid are extended vertically and may break into
smaller bubbles, and the column of fluid entrained by particles through
the interface may also break into drops. Further experiments with many
rigid particles indicate that the spatial distribution of particles
may change as the particles pass through interfaces: particles tend to form
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