Cavitation level-acoustic intensity hysteresis: experimental and numerical characterization

Pauline Labelle , Claude Inserra (1) , Jean-Christophe Béra (1)

1 Applications des ultrasons à la thérapie

In therapeutic applications such as sonoporation, inertial cavitation is commonly considered as the main candidate inducing membrane poration. Thus, characterizing inertial cavitation, as related to bubble size distribution and medium history, is of great importance. When applying successive ultrasonic shots for increasing acoustic intensities, the inertial cavitation level sharply increases around the inertial cavitation threshold. The curve of the inertial cavitation level versus acoustic intensity is different when decreasing the acoustic intensity: the threshold obtained is lower. This effect, characterized by the area of the hysteresis loop, and attributed to the change in bubble size distribution, is studied experimentally and numerically. In our experiments, when increasing the time off between two shots, the inertial cavitation curve for decreasing intensity tends towards the curve for increasing intensity. Numerically, the main mechanisms responsible for this hysteresis were identified as rectified diffusion and fragmentation during acoustic excitation, and dissolution and rising bubbles when acoustic excitation is off. Starting from a given bubble size distribution, the change in bubble size distribution is obtained for increasing and decreasing acoustic intensity. The hysteresis of inertial cavitation(quantified by bubbles collapse energy)and its dependence on time off show qualitative agreement with experimental results.

Mots clés: inertial cavitation; hysteresis; sonoporation

Domaines: Acoustique [physics.class-ph]

Pauline Labelle, Claude Inserra, Jean-Christophe Béra. Cavitation level-acoustic intensity hysteresis: experimental and numerical characterization. Acoustics 2012, Apr 2012, Nantes, France. ⟨hal-00810730⟩