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Surfactant micelles: model systems for flow instabilities of complex fluids
Christophe Perge1, Marc-Antoine Fardin, Sébastien Manneville
1École Normale Supérieure de Lyon, Laboratoire de Physique, 46 allée d'Italie, 69364, Lyon cedex 07, France.
The European Physical Journal. E, Soft Matter
|April 24, 2014
Summary
Ultrafast ultrasonic imaging reveals complex flow structures in wormlike micellar surfactant solutions, offering new insights into shear banding and elastic instabilities in complex fluids.
Area of Science:
- Rheology of complex fluids
- Fluid dynamics of soft matter
- Microstructure-flow coupling in soft materials
Background:
- Complex fluids possess microstructures that interact with external flows, leading to instabilities at low Reynolds numbers.
- Wormlike micellar solutions are model systems for studying shear banding and elastic instabilities.
- Understanding these instabilities is crucial for various industrial applications.
Purpose of the Study:
- To investigate unstable shear-banded flows in semidilute wormlike micellar surfactant solutions.
- To utilize ultrafast ultrasonic imaging for detailed analysis of flow dynamics.
- To explore the connection between microstructure, flow instabilities, and elastic turbulence.
Main Methods:
- Two-dimensional ultrafast ultrasonic imaging with frame rates up to 20,000 fps.
- Analysis of radial and azimuthal velocity components in steady and transient states.
- Characterization of vortical flow structures within shear bands.
Main Results:
- Detailed visualization of the vortical flow structure within the high shear rate band.
- Resolution of transient dynamics and fast fluctuations in micellar flows.
- Demonstration of ultrafast ultrasonic imaging as a powerful tool for studying complex fluid instabilities.
Conclusions:
- Ultrafast ultrasonic imaging provides unprecedented insights into the dynamics of shear-banded micellar flows.
- The study elucidates the complex flow structures associated with elastic instabilities.
- This technique paves the way for a deeper understanding of elastic turbulence in complex fluids.
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