A film model of sound propagation in gas-liquid foams: 2. The sound absorption

The concepts of the sound energy dissipation in gas-liquid foams are described within the frame-work of the film model of sound propagation. The high absorption of sound in foams is explained by hydrodynamic losses in foam films. The experimental dependence of the absorption coefficient on the foam expansion is explained. The calculated expansion corresponding to the absorption maximum is close to the experimental value.