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Updated: Dec 25, 2025
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Induction of Microstreaming by Nonspherical Bubble Oscillations in an Acoustic Levitation System
Published on: May 9, 2021
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Coalescence Dynamics of Acoustically Levitated Droplets.
Koji Hasegawa1, Ayumu Watanabe2, Akiko Kaneko3
1Department of Mechanical Engineering, Kogakuin University, Tokyo 163-8677, Japan.
Micromachines
|April 1, 2020
Summary
Researchers used acoustic levitation to achieve contactless droplet coalescence mid-air. This method offers insights into droplet dynamics and advances lab-on-a-drop applications.
Area of Science:
- Fluid Dynamics
- Acoustic Manipulation
- Microfluidics
Background:
- Contactless droplet manipulation is crucial for various physical and industrial processes.
- Acoustic levitation offers a versatile platform for droplet handling in lab-on-a-drop systems.
- Understanding droplet dynamics during mid-air coalescence is essential for process optimization.
Purpose of the Study:
- To investigate the mechanism of contactless droplet coalescence in mid-air using acoustic levitation.
- To experimentally and numerically explore droplet dynamics prior to coalescence.
- To provide physical insights into droplet manipulation for advanced lab-on-a-drop applications.
Main Methods:
- Utilizing an ultrasonic phased array system for acoustic levitation and controlled droplet manipulation.
- Experimentally levitating, transporting, and coalescing water droplets in mid-air.
- Employing image processing to quantify droplet curvature and simulating pressure differences for surface analysis.
Main Results:
- Observed deformation and mutual attraction of droplet edges preceding coalescence.
- Quantified droplet radii of curvature through image analysis.
- Simulated and experimentally validated a decrease in sound pressure on droplets before impact.
Conclusions:
- Acoustic levitation enables controlled contactless droplet coalescence.
- Droplet deformation and surface pressure changes are key to understanding mid-air coalescence.
- This research advances contactless droplet manipulation for future lab-on-a-drop technologies.
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