Signatures of microstreaming patterns induced by non-spherically oscillating bubbles

Area of Science:

• Fluid dynamics
• Acoustic cavitation
• Microscale phenomena

Background:

• Microbubbles are widely used in various applications, including medical imaging and drug delivery.
• Understanding the fluid flow patterns around oscillating microbubbles is crucial for optimizing these applications.
• Previous studies have primarily focused on spherically symmetric oscillations, limiting the understanding of complex flow behaviors.

Purpose of the Study:

• To investigate the theoretical and experimental aspects of axisymmetric flow surrounding non-spherically oscillating microbubbles.
• To reveal the variety of microstreaming patterns generated by microbubble oscillations.
• To establish the relationship between the bubble interface oscillation modes and the resulting fluid flow.

Main Methods:

• Theoretical modeling using exact analytical solutions for second-order mean flows.
• Analysis of microbubble interface oscillation modes (spherical, translational, nonspherical).
• Experimental investigation of fluid flow induced by a single, non-spherically oscillating bubble in an unbounded fluid.

Main Results:

• A wide variety of microstreaming patterns were identified through theoretical modeling.
• The streaming patterns were found to be highly dependent on the modal content of the bubble interface oscillation.
• Experimental results successfully validated the theoretical predictions for fluid flow induced by non-spherically oscillating microbubbles.

Conclusions:

• Non-spherical oscillations of microbubbles generate complex and diverse microstreaming patterns.
• The modal content of bubble oscillations is a key determinant of microstreaming behavior.
• The study provides a comprehensive understanding of microbubble-induced fluid flow, with implications for various scientific and technological fields.