Carlos Andres Rivera Villarreyes Global Product Specialist - FEFLOW

Hi,

FEFLOW has been tested with several benchmark exercises. One of them is the Theis' solution. You may take a look on the section 9.8.1 "[i][b]Transient Flow to a Well in a Confined and Unconfined Aquifer[/b][/i]" in the FEFLOW Book (pages 429-435).

Regards,

Carlos

Dear Giuseppe,

Alternatively, you can edit the multilayer wells directly on the FEFLOW interface. Steps: 1) select the multilayer well, 2) go to the View Components panel, 3) activate Multilayer Well - Attributes, and 4) activate ONLY the attribute to edit.
You will notice that Editor toolbar will change to the attribute, e.g. "Rate (MLW)". Here you can just type the new value.

Two additional ways if you have several multilayer wells,

a) Use Link to Parameter (s) option in the Map panel to make the MLW assignment. Here, you can create a table (excel, text file, etc.) with all the attributes and link values to MLW. If edition is needed, you can edit your table any time (outside of FEFLOW) and then re-create the link again.

b) [b]This is the very fast option![/b] ONLY available in FEFLOW 6.2.
- Export all the values of MLW. Data panel and right-click on Multilayer Well. Here you can use a Excel file, text file, etc.
- Edit your tables
- Import your map file again
- In the Map panel, right-click on re-imported map and choose [b]Quick Import[/b]

[b]Quick Import[/b] option will make the assignment automatically. No further action is required here. The trick is that every time you export FEFLOW information, you have also values of node and element numbers. Therefore if you did not modify this topology, the Quick Import will know where exactly to place the assignment again. Operation is valid for nodal and elemental assignments.

Cheers,

Carlos

Dear Debora,

If you are looking for a mathematical formation, which expresses the non-linearity between saturation and pressure, then I would recommend you to switch to the Richards-equation in FEFLOW. Here you will need to apply an empirical model, e.g. van Genuchten, to describe reduction of conductivity and others behaviors.

About the residual water depth, this could be interpreted as the residual water content. In some Soil Physics books, you will find that saturation can be expressed as the so-called saturation length or saturation depth. If you take an one-meter soil column and you include only the residual water content into it, the column of water inside this container is named residual water depth.

Cheers,

Carlos

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

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.

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

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

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

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

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