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Symmetry breaking in drop bouncing on curved surfaces.
Yahua Liu1,2, Matthew Andrew3, Jing Li1
1Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Hong Kong 999077, China.
Nature Communications
|November 26, 2015
Summary
Liquid drops hitting Echevaria leaves show asymmetric bouncing, unlike flat surfaces. This novel behavior, driven by leaf geometry, reduces drop impact time by 40%.
Area of Science:
- Fluid dynamics
- Biophysics
- Surface science
Background:
- Liquid drop impact on surfaces is common in nature and industry.
- Typically, drops maintain circular symmetry upon impact on flat surfaces.
- The complex geometry of natural surfaces can alter impact dynamics.
Purpose of the Study:
- To investigate the impact dynamics of liquid drops on Echevaria leaves.
- To understand the mechanisms behind asymmetric bouncing behavior.
- To quantify the effect of leaf geometry on drop impact parameters.
Main Methods:
- Experimental investigations using mimetic surfaces.
- Computational fluid dynamics using lattice Boltzmann simulations.
- Analysis of drop spreading, retraction, and contact time.
Main Results:
- Drops impacting Echevaria leaves exhibit asymmetric spreading and retraction along perpendicular directions.
- Leaf's convex/concave cylindrical architecture, comparable to drop size, induces asymmetry.
- Asymmetric momentum and mass distribution leads to preferential fluid pumping.
- Observed asymmetry results in approximately 40% reduction in contact time.
Conclusions:
- The cylindrical, curved geometry of Echevaria leaves dictates asymmetric liquid drop impact dynamics.
- This phenomenon offers a novel mechanism for controlling fluid-surface interactions.
- Reduced contact time has implications for applications requiring efficient liquid dispersal or adhesion.
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