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Published on: January 28, 2020
Efficiency of cargo towing by a microswimmer
1Department of Physics, Technion-IIT, Haifa, 32000, Israel.
Summary
This study reveals that while microswimmers can be highly efficient, their dragging efficiency is limited. Hydrodynamic coupling can assist in towing loads, contrary to previous assumptions.
Area of Science:
- Fluid dynamics
- Microscale transport phenomena
- Biophysics
Background:
- Microswimmers are crucial for microscale transport.
- Understanding their efficiency in towing loads is essential.
- Previous assumptions limited the understanding of hydrodynamic interactions.
Purpose of the Study:
- To derive a close-form expression for microswimmer dragging efficiency.
- To investigate the effect of finite proximity on towing efficiency.
- To analyze the role of hydrodynamic coupling in towing.
Main Methods:
- Derivation of analytical expressions for dragging efficiency.
- Approximation for finite mutual proximity.
- Numerical calculations for a rotary swimmer towing a spherical cargo.
Main Results:
- A simple close-form expression for the dragging efficiency of a distant load was found.
- An approximation for finite mutual proximity was derived.
- Dragging efficiency is always bounded from above, despite arbitrary swimmer efficiency.
Conclusions:
- Hydrodynamic coupling can assist microswimmers in towing loads.
- This finding contradicts previous assumptions about hydrodynamic interactions.
- Numerical results support the analytical findings for a rotary swimmer.
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