Coalescence of bubbles and drops in an outer fluid.
When two liquid drops touch, a microscopic connecting liquid bridge forms and rapidly grows as the two drops merge into one. Whereas coalescence has been thoroughly studied when drops coalesce in vacuum or air, many important situations involve coalescence in a dense surrounding fluid, such as oil coalescence in brine. Here we study the merging of gas bubbles and liquid drops in an external fluid. Our data indicate that the flows occur over much larger length scales in the outer fluid than inside the drops themselves. Thus, we find that the asymptotic early regime is always dominated by the viscosity of the drops, independent of the external fluid. A phase diagram showing the crossovers into the different possible late-time dynamics identifies a dimensionless number that signifies when the external viscosity can be important.
The Department of Physics, The James Franck and Enrico Fermi Institutes, The University of Chicago, 929 E 57th Street, Chicago, Illinois 60637, USA.
Joseph D
JD
Paulsen
The Department of Physics, The James Franck and Enrico Fermi Institutes, The University of Chicago, 929 E 57th Street, Chicago, Illinois 60637, USA.
Rémi
R
Carmigniani
The Department of Physics, The James Franck and Enrico Fermi Institutes, The University of Chicago, 929 E 57th Street, Chicago, Illinois 60637, USA.
Anerudh
A
Kannan
The Department of Physics, The James Franck and Enrico Fermi Institutes, The University of Chicago, 929 E 57th Street, Chicago, Illinois 60637, USA.
Justin C
JC
Burton
The Department of Physics, The James Franck and Enrico Fermi Institutes, The University of Chicago, 929 E 57th Street, Chicago, Illinois 60637, USA.
Sidney R
SR
Nagel