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Hi all,

I'm facing an issue with printing porosity in the GAIA results file: even when adding the keyword '*XKV' to the .cas file, it does not show up in the graphical output file.

For larger context, I am attempting to modify a selafin file that has a combination of characteristics from a previous computation and from the bedload, as in this thread. Since I have had no success in FORTRAN, I am instead trying Python to merge this data, and am successful in generating a file that contains the desired characteristics.
However, I am running into the issue that GAIA prefers LAY* MAS SAND* to LAY* SAND RAT* when it does its calculations. I find it easier to modify LAY* SAND RAT* as I know the relative fractions I want, so in my Python script I remove the LAY* MAS SAND* entries. When it comes time to run the GAIA previous computation file, I get an error saying that porosity information is also required in addition to the LAY* SAND RAT* and LAYER* THICKNES variables.
This led me to look in the gaia.dico file and find the 'kXKV' variable for graphic output, which is the porosity of layer k. I find it strange that this is not available in the GAIA user manual, but anyway. So I reran my prior simulation with '*XKV' in the steering file, but there was no graphical output corresponding to porosity; maybe this is why it is not mentioned in the manual. But if this is the case, 1) why is kXKV still present in the dico, 2) why doesn't kXKV output anything, 3) why can't porosity be read from the steering file where it is provided, and 4) why is kXKV required for computation continued without mass if it doesn't work? or 5) am I missing something?

In the meantime, I've tried computing mass in Python by supposing porosity = 0.6 (=1-0.4), particle density = 2650 and using layer thickness and fractions. The math works (0.6*2650*THICK*RAT for each class and layer), and the simulation runs... but this is so much more convoluted.
I would have tried to generate porosity variables which would have just been 0.6 everywhere, but I don't even know what these are named in the output file... in fact, I can't even find anything in nomvar_gaia.f that involves porosity or kXKV!

Thanks for any explanations,
André Renault

Hello André,

Looking quickly to GAIA source code, it seems that you are right.
XKV only seems to appear in the GAIA dictionary for the VARIABLES FOR GRAPHIC PRINTOUTS but nothing seems to be connected to the source code in order to print this variable.

The only things that I have seen are concerning porosity are:
- XKV0 (connected to LAYERS NON COHESIVE BED POROSITY),
- variable LAYPOR: only declared in DECLARATIONS_GAIA and not used.

Surely lack of time to do the job by my colleagues or not the most urgent.

Anyway, you can read section 6.4 of the GAIA user manual "Print a new output variable in the selafin file" if you want to save XKV (after computing it in the source files).

At last, you seem to have a gitlab account, you can create an issue.

Chi-Tuan

Hi,

I had a look and it is an error that the porosity was added in the dictionary. The porosity is constant for each layer and is not defined on each point.
It has been removed from the dictionary.