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Shape Asymmetry and Flexibility in Active Cross-Stream Migration in Nonuniform Shear
Derek C Gomes1, Tapan C Adhyapak1
1Indian Institute of Science Education and Research (IISER) Tirupati, Department of Physics, Tirupati, Andhra Pradesh 517619, India.
Physical Review Letters
|August 18, 2025
Summary
Microswimmers can cross streamlines in nonuniform shear flow due to their activity and asymmetric shape. This active cross-stream migration is influenced by hydrodynamic coupling and flagellar flexibility.
Area of Science:
- Fluid dynamics
- Microscale transport phenomena
- Biophysics
Background:
- Microswimmers are crucial for various applications, but their migration in complex flows remains challenging.
- Understanding active cross-stream migration is key to controlling microswimmer behavior.
Purpose of the Study:
- To investigate the mechanisms enabling microswimmers to cross streamlines in nonuniform shear flow.
- To identify the factors influencing active cross-stream migration.
Main Methods:
- Modeling of flagellated microswimmers in microchannel flow.
- Analysis of hydrodynamic coupling and flagellar flexibility.
- Development of a simplified theoretical framework.
Main Results:
- Activity and broken fore-aft shape symmetry are essential for crossing streamlines.
- Hydrodynamic coupling and flagellar flexibility significantly impact migration.
- Key factors driving nonlinear dynamics were identified.
Conclusions:
- The study reveals novel mechanisms for active cross-stream migration.
- Findings are applicable to both biological and artificial microswimmers.
- The hydrodynamic framework can be extended to various shear flow scenarios.
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