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Optimal free-surface pumping by an undulating carpet.
Anupam Pandey1, Zih-Yin Chen2, Jisoo Yuk3
1Mechanical & Aerospace Engineering Department and BioInspired Syracuse, Syracuse University, Syracuse, NY, 13244, USA. apande05@syr.edu.
Nature Communications
|November 25, 2023
Summary
Undulating boundaries can pump thin liquids efficiently. Researchers found an optimal wave speed for maximum liquid transport near free surfaces, inspired by nature.
Area of Science:
- Fluid Dynamics
- Soft Matter Physics
- Bio-inspired Engineering
Background:
- Undulating boundaries are observed in nature for directional liquid transport across various scales.
- Engineered devices increasingly adopt nature-inspired strategies for fluid manipulation.
- Low Reynolds number fluid transport often relies on specific boundary motion.
Purpose of the Study:
- To demonstrate large-scale liquid pumping using an undulating boundary near a free surface.
- To investigate the non-monotonic relationship between wave speed and flow rate.
- To identify optimal conditions for efficient directional liquid transport.
Main Methods:
- Experimental demonstration of liquid pumping by a two-dimensional traveling wave undulator.
- Asymptotic analysis of thin-film equations incorporating gravity and surface tension.
- Theoretical prediction of flow rate dependence on wave speed.
Main Results:
- An undulating boundary effectively generates large-scale pumping of thin liquids at the liquid-air interface.
- Flow rates exhibit a non-monotonic dependence on the traveling wave speed.
- An optimal wave speed was identified that maximizes the pumping efficiency.
Conclusions:
- Nature-inspired undulating boundaries can achieve efficient directional liquid transport.
- The proximity to free surfaces is crucial for minimizing energy dissipation during pumping.
- Understanding the optimal wave speed is key for designing effective bio-inspired fluidic devices.
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