The objective of FOAM-Coarsening is the study of the quiescent coarsening of foams as a function of the liquid fraction.
The project focuses on very wet foams which cannot be studied on ground, due to drainage effect. Conductimetry and multiple light scattering measurements will provide measurements of the liquid fraction, of the bubble structure and dynamics of the material during coarsening.
The rational for the systematic measurement vs. foam age is not just to observe and quantify coarsening, but perhaps, to obtain a reproducible self-similar distribution of bubble size. The stability of foams will also be studied in parabolic flight campaigns, giving precursor or complementary results.
The role of gravity on quiescent wet foams can be captured in two key questions:
- Is the growth law for average bubble size R~Sqrt [time], such that R dR/dt is a constant? If so, what is the liquid-fraction dependence of this rate?
- How do the rate and the nature of the bubble rearrangement dynamics change as the liquid fraction is increased to the point of un-jamming?
Current status of development
The FOAM-Coarsening experiment is planned to be integrated in an Experiment Container to be operated in the Fluid Science Laboratory.
The sample cells (~1 cm3) will be carried on a carrousel, moving in front of diagnostics: Overview camera, Speckle Variance Spectroscopy (SVS) and Diffusing-Wave Spectroscopy (DWS).
Last update: 13 May 2009