Welcome to the Getting Started with GeoStudio video series.
This tutorial introduces how to use the CTRAN/W product of GeoStudio 2012.
This tutorial video has been designed to walk new users through the basics of setting up a simple solute transport analysis in CTRAN/W.
So if you are new to CTRAN/W and are not sure where to start,
you have come to the right place.
The main topics that will be covered in the tutorial will be how to create an analysis in CTRAN/W by using:
the define view to set up the analysis, the solve manager to solve the numerical analysis,
and the options available in results view to gain a deeper understanding of the analysis.
It you are not familiar with GeoStudio Products, it is recommended that you start with the tutorial videos for SEEP/W,
SIGMA/W or SLOPE/W
to gain an understanding of the tools available for drawing your geometry domain, creating sketches,
or explanations on basic options that are available in all GeoStudio Products.
This tutorial video will mainly discuss CTRAN/W options and tools where they differ from SEEP/W, SIGMA/W or SLOPE/W.
Note, CTRAN/W is used in conjunction
with SEEP/W W or VADOSE/W to model the flow regime prior to modelling the solute transport problem.
So, let's get started.
Here is a schematic of a contaminated pond near a slope, with the water table located at the surface of the valley floor.
We will conduct two solute transport simulations:
a particle tracking analysis; and an advection- dispersion analysis.
The particle tracking analysis will be a quick way to determine the extents of the contaminated region by
simulating how individual particles would move through the soil profile with time.
The second simulation will be an advection- dispersion analysis
which will model the concentration of the contaminant plume as it advances through the profile with time.
The concentration of the contaminated pond is 10 kg per cubic meter.
Chemical diffusion is considered inconsequential and is ignored in this particular analysis.
We will start with a steady state water transfer analysis already created with our ground region already drawn.
The sketch polyline command
was used to create the drawings of our contaminated pond and valley floor water table symbol
to help visualize the problem.
If you are unsure of how to use the visualization sketching tools or draw the geometry regions, please refer to the sketching tools and geometry
video tutorial or the introduction tutorial videos to SEEP/W,
SIGMA/W or SLOPE/W.
Now we will add the material to our analysis.
I will go to KeyIn,
materials to open the materials define window.
I will add a new material and give my material a name.
I will then choose the saturated/unsaturated option from the drop down menu.
Here I can create a hydraulic conductivity and volumetric water content function for my material.
More information on the hydraulic model options can be viewed in the SEEP/W: estimating hydraulic functions tutorial video.
We will first add the volumetric water content function by clicking on the ellipsis button.
We will simply add the volumetric water content function for a silt sample material
with the saturated water content or porosity of 0.35.
We will use a coefficient of volume compressibility value of 1E-4.
Next, I will add a hydraulic conductivity function by clicking on the appropriate ellipsis button.
I will add a function using the silt volumetric water content function
and a saturated hydraulic conductivity of 0.01 m per day.
Now we will add the material to our domain by choosing draw materials.
We will simply choose to silt material and assign it to our soil region.
Boundary conditions can be created and assigned in a similar way as the materials.
I would choose KeyIn, boundary conditions
to open the define boundary conditions window.
The potential seepage face and zero pressure boundary conditions are created by default.
I will also add a new hydraulic boundary condition
to represent the height of the water in the contaminated pond.
I will use the total head boundary condition with a constant value of 10.25 m.
Now I can add the boundary conditions to my domain
to represent the water table on the valley floor, the seepage face along the slope, and the water height of the pond.
Now we are ready to add our solute transport analyses to the analysis tree.
We will go into the KeyIn analyses window
and add the advection-dispersion analysis.
Here, we will use the seepage results
from the parent steady state water transfer analysis.
We will leave the convergence settings to the default values and go into the time tab.
Here we will set the duration of the analysis to 2750 days, or approximately 7.5 years, with 50 daytime steps.
We will also leave the advanced tab settings to the default settings.
Next, we will clone this analysis to keep all of the settings we just defined in the KeyIn analyses window for the advection-dispersion analysis.
We will change the name of our analysis
and change the analysis type to particle tracking forward.
The geometry of the domain is considered project specific, but the material properties, boundary conditions, and analysis type can be modified
to simulate different scenarios of the analysis.
Now we must return to our define window and set up the solute transport properties for our analyses.
We will first define the material properties for our silt material by going into the KeyIn materials window.
Since we have already created the material in the SEEP/W analysis,
we simply need to define the solute transport properties for this material.
We will define the longitudinal dispersivity as 2 m and the transverse dispersivity as 1 m.
Decay and adsorption are not included in this analysis,
so these values will be left to the default settings.
We will also activate a 0 kg per cubic meter activation concentration.
Now we can add this material to the domain for both the advection-dispersion and particle tracking analyses.
Now we are ready to define our boundary conditions for the advection-dispersion analysis.
We will go to KeyIn, boundary conditions.
The default boundary condition of a unit concentration is already defined here.
We will add a constant concentration boundary condition to simulate the concentration of the
contaminated pond and change the value to 10 kg per cubic meter.
This boundary condition assumes that there is a continuous injection of contaminant along the bottom of the pond.
We will then also add a free exit boundary condition to allow mass to exit the slope via dispersive and advective fluxes.
Now we can add these boundary conditions to the lines representing the bottom of the pond
and the slope surface.
Our next step will be to look at the default mesh.
We can see that a default global element size is set to 1 m.
We will refine the mesh by changing this value to 0.65 m.
More information on the meshing options can be found in the engineering books or the Mesh Options and Constraints tutorial video.
Now we will go into our particle tracking analysis.
Here we will choose to draw particles along the bottom of the pond.
KeyIn, particles can also be used to enter a list of particle x-y coordinates if desired.
Here, the blue circle's indicate the starting positions of the contaminant particles.
Now we can solve all of our analyses by toggling them on in the solve manager window and clicking on the start button.
Once solved, the window will automatically change to the results view instead of the define view.
For our SEEP/W analysis, by default the total head contours will appear.
We can also see the phreatic surface as a blue dashed line and some flow paths that are painted on the screen.
When we change to the advection-dispersion analysis, we can see the contours change to the concentration contours by default.
You can change the contours that are being shown on the domain in the results window
by choosing a different contour type in the drop down menu.
You can also add new contour options by clicking on the draw contours button.
You can change the shading methods used to draw your contours,
add a legend,
or change the increments and starting and ending values of your contours.
Other items can be added by clicking on the add button
and choosing the type of results contour you would like to create.
You can add labels to your contours using the draw contour labels button and clicking on the contour lines where you want labels to be painted.
You can choose what items are activated in the results window anytime using the view preferences toolbar along the right side of the screen.
Here you can toggle on or off results information, such as the velocity vectors, contours, or you can view your mesh, boundary conditions, material
properties, or toggle on and off geometry items,
such as the regions or point numbers.
Next, we will create graphs to help us gain a better understanding of our analysis.
We will add a graph that shows the concentration profile along a vertical line in our domain.
Here, we can either click and drag a box over the desired nodes
or, while holding down the shift button, we can click at the start and at the end of the line along which nodes will be chosen.
We will change the X axis to graph the elevation of the nodes for the current time step.
We can right click on the graph or use the More button
to change the visualization of our graph.
We will simply rotate our graph so that the elevation is shown on the Y axis,
toggle on and off a legend,
and increase the size of our font.
Next we will take a look at the cumulative mass leaving the domain along the free exit boundary condition.
We will choose the location of our nodes to be along geometry items and hold down the control button on
the keyboard while clicking on both the slope and the line representing the valley floor.
We will choose mass flow, cumulative mass rate and time from the drop down menus
and use all time steps.
We will sum the Y vs. average X values.
Another way to view the results is a contour one concentration value at different elapsed times.
For example, the location of a concentration of 1 kg per cubic meter
for each time step.
The special contours are called isolines.
To create an isoline, click on draw isolines.
We will change the drop down menu to concentration and choose a value of one.
Now we will choose custom time steps for which we want an isoline to be drawn on the domain.
We will click apply and then use the draw contour labels command to draw the time step values on each of the isolines.
Now we will switch to the particle tracking analysis.
CTRAN/W has tracked the particles through the finite element mesh
using the SEEP/W computed velocities and water contents.
By default, the location of the particles for the last time step are shown.
To view the particle location during another time step, you can simply click on the time steps in the results times window.
To shade between specific particle migration paths you can choose the particle shading option
and click on the particles between which you want shading to be painted.
Individual particle information can also be viewed by choosing the view particle information button and clicking on the particle directly.
More information on the other options available in the results view can be viewed in the SEEP/W, SIGMA/W or SLOPE/W tutorial videos.
We have now reached the end of this introductory tutorial.
Note that not all of the powerful features of CTRAN/W 2012 have been used or discussed here.
Further information on each command can be found in the online help,
supporting documentation for CTRAN/W,
as well as in other tutorial videos of the Getting Started with GeoStudio video series.
Thank you for watching.