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| CTRAN/W - Contaminant transport analysis. |
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CTRAN/W is a finite element software product that can be used to model the movement of contaminants through porous materials such as soil and rock. The comprehensive formulation of CTRAN/W makes it possible to analyze problems varying from simple particle tracking in response to the movement of water, to complex processes involving diffusion, dispersion, adsorption, radioactive decay and density dependencies. You can apply CTRAN/W to the analysis and design of geotechnical, civil, hydrogeological, and mining engineering projects.
CTRAN/W is integrated with SEEP/W and has the same CAD-like interface. The two software products must be used in tandem to analyze contaminant transport. SEEP/W computes the water flow velocity, volumetric water content, and water flux. CTRAN/W uses these parameters to compute the contaminant migration. Easy to Use
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Defining a Contaminant Transport Model
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Once you have solved your flow problem with SEEP/W, you can use the graphical tools in CTRAN/W to interactively apply boundary conditions and specify material properties. Conduct a simple particle tracking analysis, or define dispersivity, diffusion, adsorption, decay and density to conduct an advection-dispersion analysis. If you make a mistake, you can correct it using the Undo command. |
Viewing the Analysis Results
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Once you have solved your contaminant transport problem, CTRAN/W offers many tools for viewing results. Generate contours or x-y plots of any computed parameter, such as concentration, mass, adsorption, dispersion, or Peclet and Courant numbers. Velocity vectors show the flow direction and rate. Examine the contaminant mass in the solid and liquid phases at any location. Transient conditions can be shown by plotting the changing concentration levels over time. Interactively query computed values by clicking on any node, element Gauss region, or flux section. Then export the results into other applications, such as Microsoft Excel or Word, for further analysis or to prepare presentations.
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Typical Applications
CTRAN/W can model almost any contaminant transport problem, including:
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Flow of contaminants from a surface pond
Flow of dissolved hydrocarbons
Flow of radioactive contaminants
Transport through fractured rock
Sea-water intrusion into coastal aquifers
Brine transport
Landfill leachate migration
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| Formulation |
When a contaminant enters the ground, the dissolved constituents will migrate due to the movement of the water. In addition, the contaminant disperses due to hydrodynamic mixing and molecular diffusion. The migration also may be retarded due to adsorption and radioactive decay. The advective-dispersive differential equation is derived by applying the principle of mass balance to an element of porous medium, with consideration of advection, dispersion, adsorption and decay.
CTRAN/W computes adsorption using the adsorption function and the computed nodal concentrations. It then computes the mass quantity in both the fluid phase and the solid phase.
CTRAN/W can also model contaminant movement by simply tracking particles from user-defined locations. For each time step, CTRAN/W moves the particles a distance based on the volumetric water content and the SEEP/W-computed water velocities.
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| Features: |
- Steady-state and transient water flow conditions through saturated and unsaturated soil systems.
- Time-dependent hydraulic boundary conditions.
- Anisotropic and heterogeneous ground conditions.
- Time-dependent concentration and mass flux boundary conditions, free exit boundary conditions.
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- Molecular diffusion coefficient as a function of volumetric water content.
- Model adsorption as a function of concentration, mass loss due to radioactive decay, and mass flux across user-specified sections.
- Particle tracking isolates advection by showing the flow path of individual particles.
- Density-dependent analysis with contaminant density different than groundwater density.
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| Use SEEP/W velocities in CTRAN/W |
One of the major components in a contaminant transport analysis is the velocity of the water, which can be obtained from a SEEP/W analysis. Once this velocity is known, it can be used in CTRAN/W to study the transport of contaminants.
Perform Density Dependent Analyses with CTRAN/W and SEEP/W
In density dependent fluid flow, the velocity of the water is dependent on the solute concentration. The water velocity in turn influences the movement of the solute. The iterative transfer of water velocity from SEEP/W to CTRAN/W and the transfer of concentration from CTRAN/W to SEEP/W makes it possible to do density dependant fluid flow analyses.
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Engineering Methodology Book |
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When you purchase a CTRAN/W 2007 license you also receive a copy of the CTRAN/W Engineering Methodology book, Transport Modeling with CTRAN/W 2007. This book is not a software manual but a full-length book that discusses why and how to model. It does not describe how to use the commands in the software or which buttons to click - that is provided in detail in the Online Help. Instead it is about thinking: how to think before, during and after setting up and solving a model. The Engineering Methodology book has chapters devoted to: |
| Material Properties
Bounday Conditions
Analysis Types
Functions in GeoStudio
Numerical Issues
Visualization of Results
Modeling Tips and Tricks
Illustrative Examples
Theory |
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| Helping Communities |
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Project Review
Ecoseal reviewed the ACIAR Project on Sustainable Agriculture in Saline Environments through Serial Biological Concentration, which was carried out in Pakistan and Australia. |
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| Read More |
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Seawater Intrusion Model for the Island of Kayts, Sri Lanka
Assessing sustainable water supply options for Kayts to limit the impact of saline groundwater upconing and saltwater intrusion along the northwest coast of Sri Lanka. |
| Read More |
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Groundwater Management Model for the Lower Murray, Australia
The aim of this project was to develop a groundwater management model which was used by natural resource managers and the community to better manage the groundwater resources of the Lower Murray. This region has been designated as a potential high-risk aquifer system.
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