scholarly journals From analytical solutions of solute transport equations to multidimensional time-domain random walk (TDRW) algorithms

2015 ◽  
Vol 51 (3) ◽  
pp. 1860-1871 ◽  
Author(s):  
Jacques Bodin
Keyword(s):  
Random Walk ◽  
Solute Transport ◽  
Analytical Solutions ◽  
Time Domain ◽  
Transport Equations

scholarly journals Study of Pollutant Transport in Environmental Flows Using Depth-Averaged Random Walk Method

10.29007/gd96 ◽  
2018 ◽  
Author(s):  
Xuefei Wu ◽  
Fan Yang ◽  
Dongfang Liang
Keyword(s):  
Random Walk ◽  
Solute Transport ◽  
Analytical Solutions ◽  
Environmental Flows ◽  
Concentration Gradients ◽  
Bed Elevation ◽  
Numerical Predictions ◽  
Parametric Studies ◽  
Transport Problems ◽  
Sharp Concentration

A depth-averaged random walk scheme is applied to investigate the process of solute transport, including advection, diffusions and reaction. Firstly, the model is used to solve an instantaneous release problem in a uniform flow, for which analytical solutions exist. Its performance is examined by comparing numerical predictions with analytical solutions. The advantage of the random walk model includes high accuracy and small numerical diffusion. Extensive parametric studies are carried out to investigate the sensitivity of the predictions to the number of particles. The result reveals that the particle number influences the accuracy of the model significantly. Finally, the model is applied to track a pollutant cloud in the Thames Estuary, where the domain geometry and bed elevation are complex. The present model is free of fictitious oscillations close to sharp concentration gradients and displays encouraging efficiency and accuracy in solving the solute transport problems in a natural aquatic environment.

scholarly journals Solute transport in aquifers of arbitrary variability: A time-domain random walk formulation

2014 ◽  
Vol 50 (7) ◽  
pp. 5759-5773 ◽  
Author(s):  
Vladimir Cvetkovic ◽  
Aldo Fiori ◽  
Gedeon Dagan
Keyword(s):  
Random Walk ◽  
Solute Transport ◽  
Time Domain

A New Time Domain Random Walk Method for Solute Transport in 1-D Heterogeneous Media

Ground Water ◽  
1997 ◽  
Vol 35 (6) ◽  
pp. 1008-1013 ◽  
Author(s):  
Olivier Banton ◽  
Frederick Delay ◽  
Gilles Porel
Keyword(s):  
Random Walk ◽  
Solute Transport ◽  
Time Domain ◽  
Heterogeneous Media ◽  
Random Walk Method ◽  
New Time

Analytical solutions to the moment transport equations-II

1985 ◽  
Vol 12 (11) ◽  
pp. 613-632 ◽  
Author(s):  
C.E. Lee ◽  
W.C.P. Fan ◽  
M.P. Dias
Keyword(s):  
Analytical Solutions ◽  
Transport Equations ◽  
The Moment

Measuring transient solute transport through the vadoze zone using time domain reflectometry

Soil Research ◽  
2001 ◽  
Vol 39 (6) ◽  
pp. 1359 ◽  
Author(s):  
I. Vogeler ◽  
S. Green ◽  
A. Nadler ◽  
C. Duwig
Keyword(s):  
Electrical Conductivity ◽  
Solute Transport ◽  
Time Domain ◽  
Deterministic Model ◽  
Soil Surface ◽  
Time Domain Reflectometry ◽  
Richards Equation ◽  
Electrical Conductivities ◽  
Destructive Measurement

Time domain reflectometry (TDR) was used to monitor the transport of conservative tracers in the field under transient water flow in a controlled experiment under a kiwifruit vine. A mixed pulse of chloride and bromide was applied to the soil surface of a 16 m2 plot that had been isolated from the surrounding orchard soil. The movement of this solute pulse was monitored by TDR. A total of 63 TDR probes were installed into the plot for daily measurements of both the volumetric water content (θ) and the bulk soil electrical conductivity (σa). These TDR-measured σa were converted into pore water electrical conductivities (σw) and solute concentrations using various θ–σa–σw relationships that were established in the laboratory on repacked soil. The depth-wise field TDR measurements were compared with destructive measurement of the solute concentrations at the end of the experiment. These results were also compared with predictions using a deterministic model of water and solute transport based on Richards’ equation, and the convection–dispersion equation. TDR was found to give a good indication of the shape of the solute profile with depth, but the concentration of solute was under- or over-estimated by up to 50%, depending on the θ–σa–σw relationships used. Thus TDR can be used to monitor in situ transport of contaminants. However, only rough estimates of the electrical conductivity of the soil solution can so far be obtained by TDR.

scholarly journals A new upscaling method for the solute transport equations

2005 ◽  
Vol 13 (4) ◽  
pp. 941-960 ◽  
Author(s):  
Zhiming Chen ◽  
◽  
Weibing Deng ◽  
Huang Ye ◽  
Keyword(s):  
Solute Transport ◽  
Transport Equations
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