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Dear Ludwig,
A non-reactive tracer does not mean that dispersivity values should be zero. The conservative tracers do not consider chemical reaction (degradation rate) and solute interchange between solid and liquid phases (i.e. adsorption). In Groundwater literature, one typically speaks about the [b]retardation coefficient[/b] in order to distinguish between reactive and conservative tracers, you may be interested to read about this.
The selection of convective and dispersive mass transport formulations in FEFLOW depends on model boundary conditions. You may take a look on White Papers Vol. I.
In addition, I recommend you the following things:
1) Try using a 3rd kind BC to simulate the interaction river-aquifer. Here you can indicate low values of conductance (transfer rates) to account for clogging effect.
2) If you want to delineate hyporheic zone, you can use the new class [b]AGE [/b] introduced recently in FEFLOW 6.2. For example, 1) a so-called [b]"age"[/b] specie can be used to identify the mixture zones of two water bodies with different origins; and 2) apply the so-called [b]"exit"[/b] specie to delineate the capture zone of the river boundary.
Cheers,
Carlos
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Hi all,
Another alternative is to set up a free drainage BC by means of a Fluid-Flux BC (Gradient) equal to the material conductivity. If you assign the correct unsaturated model and properties and model is already dried, gravity-driven flow should not occur or only at a minimum level.
If the residual water content is decreased to zero (not realistic for soils), this does not mean that model will be completely dry. It is only reflects that void space is larger to contain water. In my opinion, you should mainly focused on initial saturation values.
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Hello Ludwig,
Good to hear that you could succeed!
As an additional tip, if you have want to take all advantages of FePEST parallelization capabilities, your IFM plug-in should be able to read/write in the current FePEST working directory (e.g. in external slaves). This information can be retrieved with an environmental variable.
Cheers,
Carlos
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Dear Ludwig,
Some thoughts to complement discussion...
First a general overview, PEST creates kind of copies of both material files (FPI) and observation files (FPO) in a generalized manner. For example, a typical template file (TPF) will look like this:
[color=blue]ptf %
xxp %xxp%[/color]
where [b]xxp [/b]is a variable (material property) in FEFLOW. Every optimization iteration in a PEST run, a number is assigned to section between %...%. FePEST takes this file and connect it with the material file (FPI) in order to run a new scenario. Analogy it happens for IFM-implemented observations (see previous posts).
When you define an IFM-Implemented parameter in FePEST (additional to the “normal” parameter definition), FePEST creates a so-called ifm.tpl, which is linked to ifm.fpi.
Basically the IFM plugin should carry out the following:
1) Read material properties from an existing FPI file, for example
[color=blue]xxp 0.75[/color]
2) Assign corresponding material values to an specific FEFLOW variable
Notice that if problem contains time-varying materials, you should indicate when material assignment has exactly to occur. The IFM plug-in should complete all assignments before FEM file runs, i.e. callback PreSimulation.
With all material assigned, FEFLOW will run normally and observation points will be created. FePEST will create the result FPO file (s). PEST will read these observations, compute objective function and create a new parameter FPI file. Now the IFM plug-in has the information to read and assign new material properties in next FEFLOW run.
Cheers,
Carlos
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Hi Ludwig, could you please start/continue discussion in the FePest childboard of this forum?
I would like to organise a bit things.
Thanks,
Carlos
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Dear Quinn,
Thank you for your very detail post. It helped me to reproduce the problem and found out a bug in assignment/removal of seepage face BC in FEFLOW 6.2. (p2). I already passed request to the responsible developer.
Cheers,
Carlos
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Hello Giovanni and Ludwig,
@ Giovanni,
FePEST uses a third-party software named BeoPEST for parellalization of FEFLOW runs during the PEST optimization process. This means that FePEST will distribute some FEFLOW runs to several slaves (local, external or combination of both). External slaves can be stopped, restarted or initiated any time of the optimization progress.
In case of need for coupling several models, you can still do it with FePEST. In the automatically-generated PST files from FePEST, you will find a section "model command line" with the file named "run_model.bat". This batch file runs executable FEFLOW and PEST. Here you can place another model executable file if needed.
@ Ludwig,
From the FEFLOW website (Documentation section), you can get a short tutorial of setting-up a simple FePEST project in the User Manual of FEFLOW 6.2. There is also some guidelines for IFM Programming, although this document is out-of-date, it is quite illustrative for beginners.
By the way, today we have a free webinar about FePEST, you may be interested... Register from our website.
Regards,
Carlos
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Hello,
From my experience with both classical PEST and FePEST graphical interface, I believe that time you will need to set-up a simple plug-in to assign unsaturated parameters in FePEST is much less than time needed for learning all PEST classical workflow.
Even though, if FePEST does not cover all available parameters in FEFLOW for calibration purposes, it helps you a lot to create simple PEST files (templates, instruction and control), which can be used as basis for another complex scenarios. For instance, you can setup a FePEST project with some dummy parameters, available in the interface. You just need to define the dummy parameter as "fixed", so it will be not taken into account for the optimization problem. Subsequently, you can create PEST files automatically and edit them manually according to your needs.
Calibration of high non-linear processes such as Richards-based models is very complex and time consuming. Even, you have a vertical cross-section, it would require several FEFLOW runs. Therefore, there will be the need to parallelize the problem in PEST/FePEST.
If you opt by using FePEST and a plug-in, basically you will need to use four API functions:
IfmSetMatUnsatAirEntryPressureHead
IfmSetMatUnsatFittingCoefficient
IfmSetMatUnsatMaximumSaturation
IfmSetMatUnsatResidualSaturation
Let me know if you require further information.
Carlos
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Dear Quinn,
I reproduced your problem "Not licensed". The explanation is that you occupied all available FEFLOW license seats.
Keep in mind that: # FEFLOW opened instances + # FePEST opened instances should be equal or less than your available seats.
Let me know if you have further questions,
Carlos
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Dear Quinn,
FePEST license is included together with the FEFLOW 6.2 license. Which FePEST version do you have? Are you sure that license was correctly applied in NetLM?
Cheers,
Carlos