By: Simon Cox
From: Institute of Mathematics and Physics, Aberystwyth University
At: Instituto de Investigação Interdisciplinar, Anfiteatro
Foams are found in many situations: industrially they are used in oil extraction from porous media and for ore separation in mining, while domestically they are important in foods and personal care products. Being able to predict their behaviour in a given situation stimulates improved efficiency of industrial processes and the possibility to relate chemical formulation to rheology and hence to consumer satisfaction. Foam structure is disordered but not disorganized. I will show how the bubble-scale structure can be used as the basis for modelling the flow of foams. In particular, I will give examples of shear and contraction flows, and the sedimentation of solid objects through a foam. I will also discuss the emerging field of discrete microfluidics in which foams are confined within narrow channels. Here, correctly modelling the dissipation mechanisms is the key to accurately predicting the material response.