Download Adobe Reader

Seminar Series

"Fire and Ice: Intense bubble dynamics at high pressure"

Dr. R. Glynn Holt

Department of Mechanical Engineering
Boston University

Abstract

Cavitation bubble collapse can generate intense concentrations of mechanical energy, sufficient to erode even the hardest metals and to generate light emissions (called sonoluminescence) visible to the naked eye. In this talk we’ll describe cavitation bubble experiments carried out in spherical resonators at ambient and acoustic pressures in excess of 30 MPa. Key to our system is the ability to nucleate with temporal and spatial control, which we achieve using dielectric breakdown in water from pulsed focused laser beam arrays. Our observations show that the cloud dynamics are controlled by the repetitive emission of shock waves which reflect off of the resonator wall and converge on the resonator center. We will compare these results with single bubble collapses from a single laser beam nucleation. Our results show that steady-state bubble clouds yield more light and stronger shocks, while single bubbles collapse more rapidly and can yield exotic phenomena such as Rayleigh-Taylor jets and ice formation.

Friday, December 12th, 2014
2:30 PM
132 Fluor Daniel Building