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fractional advective-dispersive equation

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Journal Article
Published: 01 February 2009
Vadose Zone Journal (2009) 8 (1): 242–249.
...F. San José Martínez; Y. A. Pachepsky; W. J. Rawls Abstract The classical model used to describe solute transport in soil is based on the advectivedispersive equation (ADE) in which an analog of Fick's law is used to model dispersion. The fractional ADE (FADE) has been proposed to address...
FIGURES
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Ratio of RMSEs of the fractional advective–dispersive equation (FADE) and the advective–dispersive equation (ADE) applied to fit the same experimental breakthrough data as a function of the Lévy exponent α at which the FADE gave the best fit when the range of α values was scanned with a 0.05 increment. The experiment numbers correspond to Table 1.
Published: 01 February 2009
F ig . 3. Ratio of RMSEs of the fractional advectivedispersive equation (FADE) and the advectivedispersive equation (ADE) applied to fit the same experimental breakthrough data as a function of the Lévy exponent α at which the FADE gave the best fit when the range of α values was scanned
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Examples of the effect of the Lévy parameter α on the fit of the fractional advective–dispersive equation to experimental breakthrough curves: (a) Exp. 3 in Table 1, □ measured, ○ simulated with α = 2 (classical advective–dispersive equation [ADE]), • simulated with α = 1.15; and (b) Exp. 36 in Table 1, □ measured, ○ simulated with α = 2 (classical ADE), • simulated with α = 1.7.
Published: 01 February 2009
F ig . 2. Examples of the effect of the Lévy parameter α on the fit of the fractional advectivedispersive equation to experimental breakthrough curves: (a) Exp. 3 in Table 1 , □ measured, ○ simulated with α = 2 (classical advectivedispersive equation [ADE]), • simulated with α = 1.15; and (b
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Effect of the Lévy exponent α on the accuracy of the fit of the fractional advective–dispersive equation solution to breakthrough curves from selected miscible displacement experiments and on the fitted fractional dispersivity Df and pore water velocity v: (a) experiments of Biggar and Nielsen (1962) with transport of 3H+ and Cl− in Columbia loam, ○ Exp. 1, ∇ Exp. 2, □ Exp. 3, ⋄ Exp. 4 in Table 1; (b) experiments of Nielsen and Biggar (1961) with transport of Cl− in Yolo loam and Columbia silt loam, ○ Exp. 5, ∇ Exp. 6, □ Exp. 7, ⋄ Exp. 8 in Table 1; (c) experiments of Nielsen and Biggar (1961) with transport of Cl− in Oakley sand, ○ Exp. 9, ∇ Exp. 10, □ Exp. 11 in Table 1; and (d) experiments of Rao et al. (1976) with transport of 3H+ in Molokai silty clay loam and Wahiawa silty clay, ○ Exp. 36, ∇ Exp. 37 in Table 1.
Published: 01 February 2009
F ig . 1. Effect of the Lévy exponent α on the accuracy of the fit of the fractional advectivedispersive equation solution to breakthrough curves from selected miscible displacement experiments and on the fitted fractional dispersivity D f and pore water velocity v : (a) experiments
Journal Article
Published: 01 November 2008
Vadose Zone Journal (2008) 7 (4): 1207–1217.
..., the model reduces to the fractional-order advectiondispersion equation model. The model was extended to the multidimensional case with spatial anisotropy and compared with the results of field experiments. FADE, fractional-order advectiondispersion equation MADE, macrodispersion experiment D...
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Journal Article
Journal: Lithosphere
Publisher: GSW
Published: 12 November 2021
Lithosphere (2021) 2021 (Special 4): 1569736.
..., such as the long tail and the early arrival. Although the best-fitted results of the advection-dispersion equation (ADE) model and mobile-immobile model (MIM) were generally consistent with those of the BTCs, the MIM was more capable than the ADE model for characterizing the shear-induced anomalous behavior...
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Journal Article
Published: 01 November 2007
Vadose Zone Journal (2007) 6 (4): 890–898.
... system model to remain at manageable levels, it is desirable that subcomponent models be relatively simple and require few input parameters. In this work, we develop an advectivedispersive solute transport equation that includes plant uptake of water and solute and present an analytical solution...
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Journal Article
Journal: Lithosphere
Publisher: GSW
Published: 26 October 2021
Lithosphere (2021) 2021 (Special 5): 7064502.
... Random Walk (CTRW) framework [ 44 ], the Tempered Time Fractional Advection-Dispersion Equation (tt-fADE) model [ 45 ], and the nonequilibrium mobile and immobile (MIM) model [ 46 ]. The nonequilibrium mobile and immobile (MIM) model has been commonly used to describe solute transport through layered...
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Journal Article
Published: 01 February 2009
Vadose Zone Journal (2009) 8 (1): 174–176.
... curve data from previously published column studies to evaluate a numerical form of the fractional advectiondispersion equation (relative to the performance of the standard advectiondispersion equation). Although the fractional advectiondispersion equation is more general than the standard advection...
Journal Article
Published: 01 May 2011
Vadose Zone Journal (2011) 10 (2): 634–641.
... to organic matter and to mineral surfaces, primarily associated with the clay and silt fractions. The direct air to solid-phase sorption is not included in the typical derivation of retardation factors from advectiondispersion equations such as shown in Eq. [1] . Alternative equations for tracer...
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Journal Article
Published: 01 November 2004
Vadose Zone Journal (2004) 3 (4): 1353–1366.
... columns under single (lumped) and split NH 4 –N applications. The column experiments were successfully simulated using Richards' equation and an advectiondispersion model with equilibrium nonlinear sorption conditions and first-order transformation for N speciation. Using the model for the two soils...
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Journal Article
Published: 01 February 2007
Vadose Zone Journal (2007) 6 (1): 140–148.
... . 29 : 4019 – 4030 . Benson , D.A. , S.W. Wheatcraft , and M.M. Meerschaert . 2000 . Application of a fractional advectiondispersion equation . Water Resour. Res . 36 : 1403 – 1412 . Beven , K.J. , D.E. Henderson , and A.D. Reeves . 1993 . Dispersion...
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Journal Article
Published: 01 February 2008
Vadose Zone Journal (2008) 7 (1): 392–393.
...' discussion of four approaches for modeling transport: the convection–dispersion equation, the stochastic–convective model, the fractional advectiondispersion equation, and the continuous-time random walk. In Chapter 2, van Genuchten and Šimůnek (“Integrated Modeling of Vadose-Zone Flow and Transport...
Journal Article
Journal: Lithosphere
Publisher: GSW
Published: 12 October 2021
Lithosphere (2021) 2021 (Special 3): 7998907.
... coefficient ( D f ) in the space fractional advection-dispersion equation (s-FADE) with the dispersion coefficient ( D ) in the advection-dispersion equation (ADE) by six solute transport experiments at three flow rates, and they concluded that the s-FADE model could efficiently explain...
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Journal Article
Published: 29 May 2018
Journal of Environmental and Engineering Geophysics (2018) 23 (2): 171–181.
... groundwater flow of a confined aquifer can be described as ( Panday et al., 2013 ): where K is hydraulic conductivity, h is the pressure head, S s is storage coefficient, t is time, and W is a source term. Then, the one-dimensional fractional advection-dispersion equation for describing non...
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Journal Article
Published: 01 November 2000
European Journal of Mineralogy (2000) 12 (6): 1069–1082.
... as predicted from equation (10) is shown in Fig. 1. An initially sharp front at x = 0 is displaced by fluid advection and distended by diffusion/dispersion in the pore fluid. The displacement of the front with respect to its original position is a measure of the time-integrated fluid flux. The distension...
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Journal Article
Published: 01 November 2008
Vadose Zone Journal (2008) 7 (4): 1181–1190.
... western Norway . J. Struct. Geol . 19 : 563 – 571 . Pachepsky , Ya. D. Benson , and W. Rawls . 2000 . Simulating scale-dependent solute transport in soils with the fractional advectivedispersive equation . Soil Sci. Soc. Am. J . 64 : 1234 – 1243 . Patashinskii , A.Z...
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Journal Article
Published: 01 February 2008
Vadose Zone Journal (2008) 7 (1): 340–349.
... strict limitation in time-step size. Among these schemes, the fully implicit method has proven itself to be most effective in handling numerical problems associated with solving highly nonlinear multiphase flow equations. In particular, the theoretical analysis of advectivedispersive transport through...
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Journal Article
Published: 01 August 2004
Vadose Zone Journal (2004) 3 (3): 848–857.
... ; Stull, 1988 ; Arya, 1999 ). The mean turbulent transport of CO 2 as a passive gas in the surface layer can be described by the advectivedispersive transport equation with variable eddy diffusivities ( K x , K y , K z ) ( Arya, 1999 , p. 137). For the three-dimensional ( x , y , z...
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Journal Article
Published: 01 February 2000
Quarterly Journal of Engineering Geology and Hydrogeology (2000) 33 (1): 77–86.
... based on a sharp interface approximation are inappropriate. The current modelling approach is based on the advectiondispersion equation. However, key parameters in this equation are scale, density and problem specific, making the approach difficult to use predictively. The density dependence...
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