Welcome to the User Interface Video Series.
This tutorial describes the multi-physics functionality available for the GeoStudio
mass and heat flow products: SEEP/W, TEMP/W, CTRAN/W, and AIR/W.
GeoStudio's rigorous multi-physics solver offers straightforward coupling of mass and heat transfer processes.
Multiple physical processes may be simulated in a single analysis,
including water, air, solute, gas, and heat transfer processes.
The simultaneous simulation of multiple physical processes on the same domain does not require interaction between the processes.
In other words, an analysis may contain multiple physical processes that are independent of one another.
However, it is also possible to simulate one-way coupling where one process affects another,
or full coupling where there is a complete interdependence between multiple physical processes.
This functionality has a wide range of applications, including the simulation of water and heat transfer driven by climactic factors,
groundwater flow through freezing and thawing soils,
the movement of solutes and gases in the subsurface,
and forced and free convection of air within porous media like waste rock piles or dams in cold environments.
In the Define Analyses window, when a SEEP/W, TEMP/W, CTRAN/W, or AIR/W analysis is created
the Physics tab has a list of the optional physical processes that may be included in that analysis.
In this example, we have started with a SEEP/W water transfer analysis.
Thus, the water transfer option has already been selected for us.
There are four additional water transfer processes available; however, if we do not select any of these additional processes
the analysis simulates groundwater flow due to pressure and gravity driven gradients.
These are the default physical processes in SEEP/W.
Under the Water tab, we can specify the source of the initial pore-water pressure conditions for this transient analysis,
and modify the convergence criteria,
under-relaxation scheme, and values for the physical constants.
On the Physics tab, let us add heat transfer physics to this analysis.
By toggling on this option, we are choosing to simulate heat transfer using TEMP/W in the same analysis.
If we do not select any of the additional heat transfer processes, our analysis only considers conduction.
Thus, the water and heat transfer processes are completely independent in this analysis.
In other words, there is no coupling between the physical processes being simulated.
When we added heat transfer physics to this analysis, a Heat tab appeared with similar options as the Water tab.
Here we can specify the source of the initial temperatures within the domain,
set the convergence criteria,
and modify the physical constants for the latent heat of water and phase change temperature.
In the Define Materials window, there are now two tabs available for defining the material properties.
One for the thermal properties and one for the hydraulic properties of each material.
Similarly, in the Define Boundary Conditions window, there are two boundary condition categories available in the dropdown menu.
One for the thermal boundary conditions and one for the hydraulic.
When applying boundary conditions to the project domain, we may choose to view either the hydraulic or thermal boundary conditions.
You can see that both a hydraulic and thermal boundary condition may be applied to the same location.
Let us now consider an analysis with additional physical processes influencing water transfer.
In the second analysis, in the Define Analyses window, I will toggle on the physical process 'Free convection: thermal affects'.
When I select this option, water transfer depends on the temperature throughout the domain, representing one-way coupling.
When heat transfer physics are not included in the analysis, temperature results from another GeoStudio analysis are required.
Under the Heat tab, I can specify whether the heat transfer results are from the parent analysis
or from another GeoStudio analysis, either within the same project file or from an external file.
Because heat transfer was simulated in the first analysis, I can select this as the source analysis
and indicate which time steps to use the results from.
In the third analysis, I will toggle on the process 'Free convection: thermal effects' under Water Transfer, as well as the heat transfer physics.
By adding heat transfer to this analysis, there is no longer a need to obtain temperature results from a separate analysis.
Thus, the heat transfer tab provides the same options we observed in the first analysis.
The physics in this analysis also represent one-way coupling.
In the final analysis, I will choose the same physical processes as the previous analysis
but also select 'Forced convection with water transfer' under the heat transfer options.
In this case, water transfer requires information about temperature throughout the domain,
while heat transfer is also influenced by the flow of water.
Thus, this analysis includes two-way coupling of the water and heat transfer processes.
There are many other commonly used types of coupling.
For example, when water and air transfer processes are simulated on the same domain,
the respective physics will automatically be solved in a mathematically coupled manner.
This automatic coupling is required because water and air exist together in the soil pore space
so changes in the pressure of one fluid simultaneously will affect the pressures in the other fluid.
Isothermal vapor transfer is driven by pore-water pressure gradients so it does not require additional physics.
However, thermal vapor transfer requires temperature gradients and therefore requires one-way coupling to a heat transfer analysis.
Advection-dispersion contaminant transport requires information about groundwater flow through the domain
so one-way coupling to a water transfer analysis is necessary.
Free convection of water occurs due to spatial variability in density caused by variations in temperature or solute concentration.
At the same time, water flow causes forced convection of solutes or heat. As such, the water and heat, or water and solute physics
may be solved on the same domain by selecting the corresponding additional physics options.
The Benard Free Convection example illustrates coupling between these processes.
In conclusion, the Physics tab in the Define Analyses window allows for the selection of multiple physical processes for a single analysis.
The finite element equations representing the physical processes may be solved independently
or interdependently depending on the level of coupling of the various processes.
The multi-physics functionality is applicable to a wide range of problems
and the user interface provides easy definition for analyses with many physical processes.
For more information on GeoStudio and its features,
please take a look at the example files and other tutorial videos on the GEO-SLOPE website.
The Heat and Mass Transfer Engineering Book is also a valuable resource for understanding how
coupling between processes is represented mathematically in GeoStudio.
Thank you for watching.