The Curious Dynamics of Translating Bubbles: Nonspherical Shape Oscillation, Stability, and the Influence of Encapsulation

Abstract

When subject to an acoustic field, bubbles will translate and oscillate in interesting ways. This motion is highly nonlinear and its understanding is essential to the application of bubbles in diagnostic ultrasound imaging, microbubble drug delivery, and acoustic cell sorting, among others. This talk will review some of the interesting physics that occur when bubbles translate in an acoustic field, including Bjerknes forces, the added mass effect, and acoustic trapping. The influence of an encapsulating shell on the nonspherical shape oscillation and stability of a translating microbubble will be analyzed in detail and the results from recent simulations presented. The findings demonstrate the counterintuitive result that, compared to a free gas bubble, the encapsulation actually promotes instability when the microbubble translates due to an acoustic wave.

MICHAEL CALVISI

Department of Mechanical & Aerospace Engineering, University of Colorado, Colorado Springs