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Updated: Jun 26, 2026
08:01
The Diffusion of Passive Tracers in Laminar Shear Flow
Published on: May 1, 2018
Shear-induced diffusion of platelike particles in microchannels
Roberto Rusconi1, Howard A Stone
1School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts, USA.
Physical Review Letters
|December 31, 2008
Summary
Microfluidic technology reveals shear-induced diffusion in clay suspensions. Platelike particles exhibit significant cross-stream diffusion, dependent on shear rate and concentration.
Area of Science:
- Fluid dynamics
- Materials science
- Colloid science
Background:
- Collective diffusion is crucial for understanding particle behavior in fluids.
- Shear forces can significantly alter particle dynamics in suspensions.
- Microfluidic devices offer precise control for studying microparticle behavior.
Purpose of the Study:
- To investigate shear-induced diffusion in suspensions of micron-sized particles using microfluidics.
- To analyze the effect of particle shape on diffusion under shear.
- To quantify the relationship between diffusion, shear rate, and particle concentration.
Main Methods:
- Utilized advanced microfluidic technologies for controlled experiments.
- Employed suspensions of platelike clay particles.
- Measured cross-stream diffusion coefficients at low volume fractions.
Main Results:
- Platelike clay particles demonstrated significant cross-stream shear-induced diffusivity.
- Diffusion coefficient showed a linear dependence on average shear rate (10^2-10^4 s^-1).
- Diffusion scaled linearly with particle concentration and agreed with rescaled sphere data.
Conclusions:
- Microfluidics enables detailed study of collective shear-induced diffusion.
- Particle shape (platelike) is critical for observing shear-induced diffusion.
- Findings align with theoretical models and experimental data for spherical particles.
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