DYNAMICS OF 3D REAL FOAM COARSENING

Dynamics of a polydisperse 3D dry foam was experimentally investigated by means of a novel nondestructive method, more precisely by optical tomography associated to a foam reconstruction algorithm. The foam coa rsening law obeys to a 3D extension of the classical von Neumann coars ening law of 2D foams. It is obtained as [V-f](-1/3)d[V-f]/dt = k'(f - [f]). [V-f] is the mean volume of f-faced bubbles, k' a diffusion con stant equal to the single film gas diffusion coefficient, and [f] is t he mean number of faces per bubble.