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Updated: May 16, 2026
07:08
Film Control to Study Contributions of Waves to Droplet Impact Dynamics on Thin Flowing Liquid Films
Published on: August 18, 2018
How does an air film evolve into a bubble during drop impact?
Ji San Lee1, Byung Mook Weon, Jung Ho Je
1X-ray Imaging Center, Department of Materials Science and Engineering, Pohang University of Science and Technology, San 31, Hyoja-dong, Pohang 790-784, Korea.
Physical Review Letters
|December 11, 2012
Summary
Air gets trapped under liquid drops impacting surfaces. Ultrafast imaging revealed this trapped air evolves into a bubble through retraction, contraction, and pinch-off, with surface wettability influencing bubble detachment.
Area of Science:
- Fluid dynamics
- Surface science
- Microscopy
Background:
- Liquid drop impact on solid surfaces is common.
- Air entrapment beneath impacting drops is a known phenomenon.
- Understanding the dynamics of entrapped air is crucial for various applications.
Purpose of the Study:
- To visualize the dynamic evolution of entrapped air during drop impact.
- To identify the distinct stages of air film transformation into a bubble.
- To investigate the influence of surface wettability on bubble detachment.
Main Methods:
- Utilized ultrafast X-ray phase-contrast imaging.
- Directly visualized the air film profile and its evolution.
- Analyzed the energy transfer driving the process.
Main Results:
- Identified a three-stage evolution process: inertial retraction, bubble contraction, and daughter droplet pinch-off.
- Demonstrated that energy transfer during retraction fuels bubble formation and pinch-off.
- Observed that surface wettability significantly impacts bubble detachment.
Conclusions:
- The study provides direct visualization of a complex air entrapment evolution.
- Surface wettability offers a potential method to control or eliminate bubbles in drop-impact scenarios.
- Findings have implications for optimizing processes involving liquid-solid interactions.
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