Coupled oscillations of microbubbles under ultrasound and hydrodynamic consequences
Vendredi 16 octobre 2015 14:00
- Duree : 2 heures
Lieu : Conference room - LIPhy - Bât E - 140 Avenue de la Physique - St Martin d’Hères. Accès par interphone, appeler le secrétariat
Orateur : Soutenance de Thèse de Flore MEKKI-BERRADA
The pulsation properties of air bubbles under ultrasound have received much attention since the development of sonoporation and contrast agen ts. Spherical bubbles are well-known to induce streaming when excited by ultrasound. We report here the acoustic vibration of microbubbles confined between the two walls of a microfluidic channel. These bubbles exhibit a volume pulsation at low intensities of ultrasound, with an additional parametric surface mode for higher intensities of the pressure field. Because the channel walls are elastic, the bubble pulsation leads to the generation of Rayleigh waves at the channel wall interface. The bubble coupling induced by these surface waves has substantial hydrodynamic consequences. In fact, neighboring bubbles will excite the translation mode of the bubble in addition to its volume pulsation, which gives rise to long-range mixed-mode streaming. Using a large triangular lattice of these microbubbles, we finally obtain a unique acoustic bubble “pinball” driving fluid and particles in complex paths.
Contact : flore.mekkiberrada@ujf-grenoble.fr
Discipline évènement : (Physique)
Entité organisatrice : (LIPhy)
Nature évènement : (Soutenance de thèse)
Site de l'évènement : Domaine Universitaire de St Martin d’Hères
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