The fascination of foams

Simon Cox

(Institute of Mathematics and Physics, Aberystwyth University)

Foams are used in many industrial and domestic applications and so trying to predict their behaviour is a worthwhile goal. I will describe a number of areas in which computer science contributes to achieving this goal.

Firstly, the local geometric structure of a foam has a particular appeal due to the simplicity of the laws of equilibrium, themselves based upon a minimum energy principle. Determining the optimal geometric structure, that is the lowest energy minimum, is a non-trivial problem even in two dimensions (2D). I will show how it can be viewed as a problem in the enumeration of planar graphs.

Whether as a test of theoretical predictions or as an exploratory tool in its own right, tomographic imaging of unstable 3D foams is now a reality. The large data sets that result require the development of new tools both to extract useful information, such as local bubble deformation and velocity, and to present this information in a meaningful and accessible manner.

Finally, rheological flows of foams can be simulated with a number of numerical techniques that probe the flow on the bubble scale. This is usually a very slow computation and moving to a parallel code is not always possible. I will indicate the approximations inherent in these codes and the results that emerge.
Tuesday 10th November 2009, 14:00
Robert Recorde Room
Department of Computer Science