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Vacillating breathing and tumbling of vesicles under shear flow
1Laboratoire de Spectrométrie Physique, UMR, Université Joseph Fourier and CNRS, 140 avenue de la physique, 38402 Saint Martin d'Heres, France.
Physical Review Letters
|February 21, 2006
Summary
Researchers analyzed vesicle dynamics in shear flow, discovering a novel "vacillating-breathing" motion where vesicles oscillate orientation and change shape. This behavior coexists with tumbling, and a tumbling threshold was determined.
Area of Science:
- Fluid dynamics
- Biophysics
- Rheology
Background:
- Vesicles, crucial biological structures, exhibit complex behaviors in fluid flows.
- Understanding vesicle dynamics is essential for fields ranging from cell biology to materials science.
Purpose of the Study:
- To analytically investigate the behavior of vesicles under shear flow in the small deformation regime.
- To identify and characterize novel dynamic modes of vesicles in shear flow.
Main Methods:
- Derivation of two coupled nonlinear equations governing vesicle orientation and shape evolution.
- Analytical treatment of vesicle dynamics in the small deformation limit.
Main Results:
- Identification of a new dynamic mode termed "vacillating-breathing," characterized by oscillating orientation and shape changes.
- Demonstration that this vacillating-breathing mode coexists with vesicle tumbling.
- Derivation of an explicit expression for the tumbling threshold.
Conclusions:
- The study reveals complex vesicle dynamics beyond simple tumbling in shear flow.
- The findings provide a theoretical framework for understanding vesicle behavior and its implications for suspension rheology.
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