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Updated: Jan 23, 2026
07:08
Film Control to Study Contributions of Waves to Droplet Impact Dynamics on Thin Flowing Liquid Films
Published on: August 18, 2018
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Weakly charged droplets fundamentally change impact dynamics on flat surfaces
1Department of Mechanics and Aerospace Engineering, Southern University of Science and Technology, Shenzhen 518055, China. dengww@sustech.edu.cn and Mechanical Engineering Department, Virginia Tech, Blacksburg, VA 24061, USA.
Soft Matter
|June 14, 2019
Summary
Charged droplets fundamentally alter gas film dynamics upon impact. A critical charge level deforms droplets, forming a liquid tip that pierces the gas film, preventing gas entrapment and enabling new applications.
Area of Science:
- Fluid Dynamics
- Surface Science
- Electrostatics
Background:
- Neutral droplets form a gas film upon impact, creating a lens shape.
- Charged droplets, common in nature and industry, have different impact behaviors.
Purpose of the Study:
- To investigate how electric charges affect droplet impact dynamics.
- To determine the critical charge level for altering gas film behavior.
Main Methods:
- Experimental analysis of droplet impact with varying charge levels.
- Theoretical modeling of forces acting on the droplet during impact.
Main Results:
- A critical charge level (∼1% of Rayleigh limit) triggers significant changes in droplet deformation.
- Maxwell stress overcomes gas pressure, forming a conical liquid tip that pierces the gas film.
- The outward moving contact line prevents gas entrapment, with critical charge depending on gas viscosity.
Conclusions:
- Electric charges fundamentally alter droplet impact, enabling gas-free contact.
- Findings offer insights into phenomena from raindrop impacts to industrial processes like additive manufacturing.
- This research provides a pathway to mitigate defects by controlling droplet charge.
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