damian

I've just run a transient simulation on a very simple example dam with a less permeable core than the rest of the dam. The model is not stable on the landside-border of the core and the "sustain body". But what can I do?

Another question: I still don't understand why the example dam6.fem isn't converging? I have not changed anything from the original file.

Hi Peter!

I have a problem defining the van Genuchten function. I only have values for the saturated and the residual volumetric water contents, and of course the van Genuchten parameters A and n. FEFLOW ask me the saturated and residual saturations and the porosity. Knowing the porosity it is easy to calculate the saturation from the water content. But I don't know the porosity.

Studying relevant equation I tried to assume a random porosity greater than the saturated water content and smaller than 1. Then I calculated the congruent saturations with S=theta/n and entered the random porosity as the porosity.

Varying the porosity (and of course the congruent saturations) the results were always the same. My conclusion is that the program uses the saturations and the porosity to calculate the volumetric water contents.

Is that right?

Thank you for your answer. I will try to run a transient simulation!

Yes, with the search function I can answer the question about Storytivity and Storage compressibility. But I can't find any answer for the first question. Why can't I/FEFLOW produce a convergence?

I've just found the option "AMR". Is it possible that this options solves my problem?

AND: I don't realy now what the "Storativity" and the "Storage copressibility" are supposted to be. Could you explain what the parameters describe and which values I should use?

I'm working with FEFLOW 5.4 for my masterthesis and I want to calculate zoned earth dams with a constant Head on the upside of the dam and a free seepage face on the downside (unsaturated condition, steady, flow only). I don't have any problems to simulate homogenious dams.

When I want to simulate a zoned earth dam, I'm not able to reach a convergence. The error is always bigger than something like 6.7E-2.
When I then start a Re-Run, the results are not the same. Anytime I do a Re-Run the program calculates a different result. I've already tried to enrich the mesh but there's no change of the program-behavior.
Then I found the SAMG solver package in the manuals, which should reach a convergence for problems where the PCG-solver has difficulties. But when I do the simulation, FEFLOW calculates just nonsense. There's a constant hydraulic head on the whole dam and absolutely no water flux.

Then I found the example in the FEFLOW folders "dam6.fem". But when I start the calculations there are the same problems:
a) The program isn't able to reach a convergence for a error tolerance 1E-3 (which is the default value)
b) Every Re-Run calculates different results.

I don't think that this is normal. What am I doing wrong? Or is there just something that I don't understand?