Dynamics of viscous vesicles in shear flow
M-A Mader1, V Vitkova, M Abkarian
1Laboratoire de Spectrométrie Physique, CNRS/Université J. Fourier - Grenoble I, BP 87, 38402, Saint Martin d'Hères, France.
The European Physical Journal. E, Soft Matter
|April 12, 2006
Summary
Giant lipid vesicles exhibit distinct behaviors in shear flow, transitioning between tank-treading and tumbling motions based on internal and external viscosity. This research aids in understanding blood flow dynamics.
Area of Science:
- Biophysics
- Fluid Dynamics
- Soft Matter Physics
Background:
- Giant lipid vesicles (GLVs) are model systems for biological cells.
- Understanding vesicle behavior in flow is crucial for cell mechanics and rheology.
- Previous studies explored vesicle dynamics theoretically and numerically.
Purpose of the Study:
- To experimentally investigate the flow regimes of giant lipid vesicles under shear flow.
- To characterize the transitions between different dynamic behaviors.
- To provide data for validating theoretical and numerical models.
Main Methods:
- Experimental observation of GLVs subjected to controlled shear flow.
- Varying parameters such as viscosity ratio, reduced volume, and shear rate.
- Microscopic imaging to analyze vesicle deformation and motion.
Main Results:
- Two primary flow regimes were identified: tank-treading and tumbling.
- Tank-treading occurs at low viscosity ratios, with stable membrane motion.
- Tumbling occurs at higher viscosity ratios, characterized by whole vesicle rotation.
- At increased shear rates, tumbling motion shows deviations from simple models due to deformation.
Conclusions:
- Experimental findings align with theoretical and numerical predictions for vesicle flow regimes.
- The study provides essential data for validating models of deformable particle suspensions.
- Characterizing these dynamics is key to understanding the rheology of complex fluids like blood.
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