Dissipation of ultrasonic and audible sound waves in liquid foams
Résumé
Recent results have shown the rich dynamical properties of liquid foams when submitted to an acoustic wave. However the mechanisms responsible for the observed strong attenuation are still unclear.
In this paper we collect and compare the main results concerning dissipation of two separate studies investigating the propagation of sound waves in liquid foams.
The first one developed a model to describe the different behaviours observed at ultrasonic frequency (60-600 kHz); a reasonable agreement with experiments was found by adding a phenomenological term of dissipation. In the second study the measurement of a dissipative term of unknowm origin was performed in the audible range (0.2-5 kHz). The aim of the present paper is to make a link between the dissipation found in these two studies: by comparing the results, we find a similar value for both dissipation terms, suggesting a common origin, even if they emerge in completely different frequency ranges.