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Civil and Environmental Engineering Faculty Publications
Resident concentration; Flux concentration; Diffusion-limited transport; Back-diffusion; Mobile–immobile model; Upscaled advection dispersion equation
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An Upscaled Approach For Transport In Media With Extended Tailing Due To Back-Diffusion Using Analytical And Numerical Solutions Of The Advection Dispersion Equation, Jack C. Parker, Ungtae Kim
An Upscaled Approach For Transport In Media With Extended Tailing Due To Back-Diffusion Using Analytical And Numerical Solutions Of The Advection Dispersion Equation, Jack C. Parker, Ungtae Kim
Civil and Environmental Engineering Faculty Publications
The mono-continuum advection-dispersion equation (mADE) is commonly regarded as unsuitable for application to media that exhibit rapid breakthrough and extended tailing associated with diffusion between high and low permeability regions. This paper demonstrates that the mADE can be successfully used to model such conditions if certain issues are addressed. First, since hydrodynamic dispersion, unlike molecular diffusion, cannot occur upstream of the contaminant source, models must be formulated to prevent “back-dispersion.” Second, large variations in aquifer permeability will result in differences between volume-weighted average concentration (resident concentration) and flow-weighted average concentration (flux concentration). Water samples taken from wells may be regarded …