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 coarsening law obeys to a 3D extension of the classical von Neumann coarsening law of 2D foams. It is obtained as 〈Vf〉^-1/3d〈Vf〉/dt0ex0ex=0ex0exk^'(f-〈f〉). 〈Vf〉 is the mean volume of f-faced bubbles, k^' a diffusion constant equal to the single film gas diffusion coefficient, and $〈f〉$ is the mean number of faces per bubble.