Molecular dynamics simulation versus continuum mechanics for a sonoluminescing bubble

✍ Scribed by B. Metten; T. Kurz; W. Lauterborn

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 40 KB
• Volume: 121-122
• Category: Article
• ISSN: 0010-4655
• DOI: 10.1016/s0010-4655(06)70103-5

✦ Synopsis

A small bubble in a liquid, subjected to an ultrasonic field, can be driven into stable, strongly nonlinear radial oscillations. The bubble then undergoes heavy collapse in each acoustic cycle, giving rise to extreme conditions within the bubble, associated with high temperatures and pressures, shock wave emission, chemical reactions and even light emission (singlebubble sonoluminescence). A great variety of theories have been proposed to explain sonoluminescence. One promising model assumes the formation of a converging shock wave inside the bubble and the emission of bremsstrahlung from ionized gas to account for the light emission.

Up to now the corresponding numerical calculations have been based primarily on continuum methods of gas dynamics and thermodynamics. We propose an alternative approach to bubble physics and sonoluminescence by molecular dynamics. First results of hard-sphere event-driven molecular dynamics simulations of spherical and ellipsoidal bubbles are presented. Compared to continuum models, they better describe the situation in the center of the bubble and in the shock front. We believe that molecular dynamics holds a great potential to investigate nonsphefical bubble motion and the dynamical processes within a bubble.