February 17, 2003

BUBBLE JUGGLE AND WIGGLY WORMS


Wiebke Drenckhan


BUBBLE JUGGLE: Bubbles are amazingly stable creatures. Sticking bubbles of equal size together to create an ordered foam structure and make these structures flow through channels of appropriate geometries gives rise to very beautiful experiments which allow us to study rheological properties of foam flow in a very systematic way. Using ferrofluids as the continuous medium of the foam adds an interesting variety of possibilities of remote manupulation and detection of these structures. I will present some experiments, simulations and theoretical models which we consider as first steps on the way  to the application of ferrofluid foam flow in the field of micro-fluidics and Lab-on-a-Chip technologies.

WIGGLY WORMS: On the way to an understanding of the dynamics of and in foams one encounters a variety if instabilities. Of particular interest to us at the moment is the instability of a jet of soap solution flowing down between two vertical glass plates. As simple as the system seems, it displays a number of very surprising properties...