title: On the physical origin of conical bubble structure under an ultrasonic horn.
abstract: The cavitation field generated by an ultrasonic horn at low frequency and high power is known to self-organize into a conical bubble structure. The physical mechanism at the origin of this bubble structure is investigated using numerical simulations and acoustic pressure measurements. The thin bubbly layer lying at horn surface is shown to act as a nonlinear thickness resonator that amplifies acoustic pressure and distorts acoustic waveform. This mechanism explains the self-stabilization of the conical bubble structure as well as the generation of shock wave and the focusing at very short distance.
authors.affiliation: Institut d'Electronique de Microélectronique et de Nanotechnologie, département ISEN, UMR CNRS 8520, 41 boulevard Vauban, 59046 Lille cedex, France. dubus@isen.fr
authors.forename: Bertrand
authors.initials: B
authors.lastname: Dubus
authors.forename: Christian
authors.initials: C
authors.lastname: Vanhille
authors.forename: Cleofé
authors.initials: C
authors.lastname: Campos-Pozuelo
authors.forename: Christian
authors.initials: C
authors.lastname: Granger
mesh_terms: D003198:Computer Simulation; D005740:Gases / Q000737:chemistry* / Q000528:radiation effects*; D045423:Microbubbles; D008956:Models, Chemical; D013010:Sonication
chemical_list: D005740:Gases