Direct visualization of shear waves in viscoelastic fluid using microspheres
C Labuda1, C M Tierney1, E G Sunethra K Dayavansha1
1Department of Physics and Astronomy, University of Mississippi, University, Mississippi 38677, USA cpembert@olemiss.edu, cmtierne@go.olemiss.edu, sdayavan@go.olemiss.edu, jgladden@olemiss.edu.
The Journal of the Acoustical Society of America
|June 22, 2015
Summary
Viscoelastic wormlike micellar fluids support shear waves. Microsphere seeding offers a viable alternative to birefringence for visualizing shear waves and measuring fluid attenuation, especially at low concentrations.
Area of Science:
- Rheology
- Soft Matter Physics
- Fluid Dynamics
Background:
- Wormlike micellar fluids exhibit viscoelastic properties.
- These viscoelastic fluids can support the propagation of shear waves.
- Understanding shear wave behavior is crucial for characterizing fluid dynamics.
Purpose of the Study:
- To visualize shear waves in a 500 mM CTAB-NaSal micellar fluid.
- To compare microsphere seeding with birefringence for shear wave visualization.
- To evaluate the potential of microsphere displacement for measuring fluid attenuation.
Main Methods:
- Seeding the micellar fluid with polyethylene microspheres (212–250 μm diameter).
- Visualizing shear waves through particle displacement.
- Comparing microsphere visualization with birefringence induced by shear stress.
- Measuring shear wave speeds and particle displacement patterns.
Main Results:
- Shear wave speeds were measured as 733 mm/s (microspheres) and 722 mm/s (birefringence).
- Particle displacement followed a sinusoidal function of time.
- Displacement amplitude decreased quadratically with distance from the source.
Conclusions:
- Microsphere seeding is a valid method for visualizing shear waves in wormlike micellar fluids.
- Particle displacement measurements can quantify attenuation, even when birefringence fails at low concentrations.
- This technique enhances the study of viscoelastic fluid dynamics.
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