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Updated: Dec 15, 2025
08:01
The Diffusion of Passive Tracers in Laminar Shear Flow
Published on: May 1, 2018
8.9K
Flow transiency on analytical modeling of subsurface solute transport
1School of Earth and Environment, Anhui University of Science and Technology, Huainan, 232001, China.
Summary
Groundwater solute transport is sensitive to variable flow velocity and dispersivity. Accounting for time-dependent flow velocity and distance-dependent dispersivity is crucial for accurate subsurface hydrology models.
Area of Science:
- Environmental science
- Hydrology
- Geophysics
Background:
- Groundwater flow velocity and dispersivity are often assumed constant in solute transport models.
- Temporal and spatial variability in these parameters can significantly impact model accuracy.
Purpose of the Study:
- To develop and analyze mathematical models for solute transport considering time-dependent flow velocity and distance-dependent dispersivity.
- To investigate the sensitivity of breakthrough curves (BTCs) to these variable parameters.
Main Methods:
- Coupling temporally exponential flow velocity and linearly-asymptotic or exponential distance-dependent dispersivities with the advection-dispersion equation.
- Deriving one-dimensional semi-analytical solutions using the Laplace transform in a finite domain.
- Verifying solutions with finite-element COMSOL Multiphysics numerical simulations.
Main Results:
- Solute transport is highly sensitive to temporal variations in flow velocity.
- Dispersivity's growth rate affects early and late-stage solute concentrations differently for linear-asymptotic and exponential functions.
- Increased steady-state velocity and asymptotic dispersivity amplify advection and dispersion impacts, respectively.
Conclusions:
- Time-dependent flow velocity and distance-dependent dispersivities significantly influence subsurface solute transport.
- These variable parameters are not negligible in hydrological modeling and require careful consideration for accurate predictions.
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