Art of Science 2013 Online Gallery
Talal T. Al-Housseiny (graduate student), Matthieu Roché
(postdoc), and Howard A. Stone (faculty)
Department of Chemical and Biological Engineering
Whether you are looking up at the clouds or watching coffee and milk
swirl in your cup of cappuccino, you are witnessing the complex
patterns that naturally occur as different fluids interact with each
other. Here we see the pattern that occurs as air is injected into
glycerine (a viscous substance used in a wide range of applications).
The mismatch in viscosity between these two fluids prompts the sudden
growth and splitting of air passages that branch into what to us looks
like the petals of an exotic flower. Less poetically, this phenomenon
is an "interfacial instability" known in the field of fluid dynamics as
"viscous fingering," a name inspired by the finger-shaped air passages.