Virtual MEchanics GAthering -MEGA- Seminar: On the dynamics of entrapped microbubbles for acoustic streaming and thrust generation

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Event details

Date and time 22.04.2021 16:1517:30  
Place and room
https://epfl.zoom.us/s/84678428267 Passcode: 174387
Online https://epfl.zoom.us/s/84678428267
Speaker Amit Dolev (MICROBS, EPFL)
Category Conferences - Seminars
Abstract Microbubbles in acoustic fields oscillate and give rise to acoustic radiation forces and drag-induced acoustic streaming. These forces are used for various biomedical applications such as targeted drug delivery, on chip particle manipulation, microfluidic mixing, and actuating robotic devices. Microbubbles are usually trapped inside microfabricated cavities for the application of anisotropic forces where only parts of the bubbles oscillate. In this configuration, the existing analytical models derived for spherical bubbles are insufficient.

The conventional wisdom is that bubbles should be excited at their first resonance frequency to obtain good performances, although, they have infinite resonance frequencies. To estimate the natural frequencies and the correlated normal vibration modes, we developed a new model for an arbitrary shaped and entrapped bubble that has multiple circular openings. The semi-analytical model captures a more realistic geometry via a solution to an optimization problem. The vibration modes and natural frequencies are then used to compute the acoustic streaming patterns and generated thrust via a finite element simulation. We built an experimental platform to directly measure the deflection of the bubble and visualize the generated streaming patterns. However, the model was not completely validated due to the nonlinear multiphysics nature of the problem. The complexity of the problem highlights the contribution of our simplified model as a design tool.

Bio Amit Dolev joined the MicroBioRobotic Systems Laboratory headed by Prof. Sakar as a postdoctoral associate in January 2020. He received his B.Sc. in Mechanical Engineering at Technion – Israel Institute of Technology and Ph.D. in the Dynamics Laboratory headed by Professor Izhak Bucher at the Technion-IIT during a direct doctoral track. Currently, he works on the utilization of acoustics for powering microscale technologies. He pursues a broad range of research interests including nonlinear dynamics, fluid-structure interactions, vibrations, signal processing, acoustics, and control.
 

Practical information

  • General public
  • Free

Organizer

  • MEGA.Seminar Organizing Committee

Tags

Solids Structures Fluids

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