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Updated: Sep 14, 2025
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Measuring the Interaction Force Between a Droplet and a Super-hydrophobic Substrate by the Optical Lever Method
Published on: June 14, 2019
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Droplet Impact on Superhydrophobic Surfaces Under High Pressures
Yan Yan1, Zhongqi Liu1, Muhammad Amjad1
1Institute of Thermodynamics, Technical University of Munich, 85748, Munich, Germany.
Small Methods
|July 25, 2025
Summary
This study explores droplet impact at high ambient pressures (up to 200 bar) on superhydrophobic surfaces. Complete droplet bouncing is achieved at higher pressures, advancing understanding for applications like deep-sea oil separation.
Area of Science:
- Fluid Dynamics
- Surface Science
- High-Pressure Physics
Background:
- Droplet impact research is limited to 100 bar.
- Behavior of droplets at higher pressures is largely unknown.
Purpose of the Study:
- Investigate droplet impact dynamics under high ambient pressure (up to 200 bar).
- Explore the influence of pressure and substrate topology on droplet behavior.
- Identify droplet impact regimes and develop a predictive model.
Main Methods:
- Experimental investigation of droplet impact on superhydrophobic surfaces.
- Controlled variation of ambient pressure and substrate properties.
- Observation and analysis of droplet bouncing, satellite droplet formation, and gas entrapment.
Main Results:
- Identified four distinct impact regimes: no bouncing, bouncing with gas entrapment and satellite retention, bouncing with gas entrapment, and complete bouncing.
- Droplet bouncing capability significantly increases with ambient pressure.
- Complete bouncing achieved for all tested substrates at pressures ≥ 175 bar.
- Developed a phenomenological model incorporating enhanced cushioning and hydrodynamic impact dynamics.
Conclusions:
- Droplet impact behavior is pressure-dependent, with higher pressures promoting complete bouncing.
- The developed model explains satellite droplet disappearance using a modified water hammer coefficient.
- This research extends droplet impact studies to 200 bar, relevant for high-pressure applications like deep-sea oil/water separation.
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