Laboratory and field experiments have shown that dispersivity is one of the key parameters in contaminant transport in porous media and varies with elapsed time. This time-dependence can be shown using a time-variable dispersivity function. The advantage of this function as opposed to constant dispersivity is that it has at least two coefficients that increase the accuracy of the dispersivity p...

this paper presents a simple yet powerful original approach for approximating dispersivity in porous media. the key to this approach is both use of least-squares criterion and image processing technique. two dimensional transparent models, including horizontal and vertical configurations, under different combinations of grain sizes and pore velocities, experimented. concentration data were obta...

Highly resolved numerical simulations are conducted to evaluate the longitudinal and transverse dispersivities proposed for use in the larger-scale Yucca Mountain saturated zone (SZ) site-scale model. Two different stochastic continuum models (SCM) that define the spatial variability of permeability are inferred from the observed fracture characteristics and the measured permeabilities. These m...

This paper presents a simple yet powerful original approach for approximating dispersivity in porous media. The key to this approach is both use of least-squares criterion and image processing technique. Two dimensional transparent models, including horizontal and vertical configurations, under different combinations of grain sizes and pore velocities, experimented. Concentration data were obta...

The Domenico solution is widely used in several analytical models for simulating ground water contaminant transport scenarios. Unfortunately, many textbook as well as journal article treatments of this approximate solution are full of empirical statements that are developed without mathematical rigor. For this reason, a rigorous analysis of this solution is warranted. In this article, we presen...

Tests on several scales were analyzed and conducted in a dolomite aquifer of southeastern Wisconsin to examine the variation of hydraulic conductivity and longitudinal dispersivity with scale of measurement. Scale behavior of hydraulic conductivity was shown to be dependent on the hydrofacies. In vuggy fades dominated by porous flow hydraulic conductivity increased relative to scale linearly wi...

The general expressions for the time-dependent ensemble averages of the second spatial moments ^A& and the effective dispersivities g, defined as (1/ 2m)(d^A&/dt) where m is the magnitude of the mean flow velocity m, are evaluated in order to study the effect of initial plume size on ^A& and g in three-dimensional heterogeneous isotropic aquifers under the first-order approximation to the parti...

In this paper we discuss the numerical modelling of two inverse problems in porous media flow. In the first problem, we determine the soil parameters that occur in the retention and hydraulic permeability curves of the Van Genuchten ansatz for Richard’s equation. In the second problem we determine the hydraulic permeability, longitudinal dispersivity and adsorption isotherms using the measureme...

Dispersive soils which occur in many parts of the world are easily erodible and segregate in water pose serious problems of stability of earth and earth retaining structures. The mechanism of dispersivity of soils is reasonably well understood. However there is simple method to identify the dispersivity of the soils and even more difficult to quantify the dispersivity. Visual classification, At...

[1] This study proposed a new mobile‐immobile model (MIM) to describe reactive solute transport with scale‐dependent dispersion in heterogeneous porous media. The model was derived from the conventional MIM but assumed the dispersivity to be a linear or exponential function of travel distance. The linear adsorption and the first‐order degradation of solute were also considered in the model. The...