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Updated: Sep 4, 2025
08:01
The Diffusion of Passive Tracers in Laminar Shear Flow
Published on: May 1, 2018
8.7K
Dispersion tensor in stratified porous media
Morteza Dejam1, Hassan Hassanzadeh2
1Department of Petroleum Engineering, College of Engineering and Applied Science, University of Wyoming, 1000 East University Avenue, Laramie, Wyoming 82071-2000, USA.
Physical Review. E
|July 20, 2022
Summary
We generalized Taylor dispersion theory for stratified porous media, revealing complex tracer transport behaviors like uphill advection and dispersion barriers due to hydrodynamic coupling.
Area of Science:
- Fluid dynamics
- Geophysics
- Environmental engineering
Background:
- Dispersion in porous media is crucial across scientific disciplines.
- Existing models often lack generalizations for stratified media.
- Taylor dispersion theory is well-established but limited in stratified scenarios.
Purpose of the Study:
- To generalize Taylor dispersion theory and Stokes flow for stratified porous media.
- To develop a reduced-order model for tracer dispersion in these media.
- To investigate the impact of hydrodynamic coupling on tracer transport.
Main Methods:
- Generalization of Taylor dispersion theory.
- Application of Stokes flow in porous media.
- Derivation of a reduced-order model for tracer dispersion.
- Analysis of two-layer stratified porous media.
Main Results:
- Hydrodynamic coupling in two-layer media induces tensorial dispersion and advection.
- Dispersion and advection matrices are asymmetric unless layers are uniform.
- Observed phenomena include dispersion barriers, uphill dispersion/advection, and osmotic dispersion.
- Uphill advection allows countercurrent tracer transport between layers.
- In Darcy flow, Taylor dispersion is absent; mixing relies on cross-diffusive flux.
Conclusions:
- Stratified porous media exhibit complex tracer transport beyond standard Taylor dispersion.
- Hydrodynamic coupling significantly alters dispersion and advection characteristics.
- Field-scale mixing may arise from modified advection and cross-layer diffusion, not solely Taylor dispersion.
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