• Re: Modeling advice, inflow tunnels.

    Thanks for your answer,

    Well, I think it's not related to convergence criteria or something like that. It's just unreasonable that (see picture attached above) that a tunnel like that gets almost 60% of the recharge as a water budget, by considering its relative size with the modeled area.

    The distribution shows indeed that the water budget in the tunnel is somewhat homogenous with specific zones of higher inflows due to the faults, but it's not that different from the model without faults, so I discard this to be the cause of the wrong results.

    And the model was only calibrated by considering the water heads on surface, not the water inflows into the tunnel.

    Kind regards,
  • Modeling advice, inflow tunnels.

    Hello, ;)

    I am like in a stage of my project where I need to calibrate by trial and error my model. It's a region, with twin tunnels. The model has also discrete features (vertical faults), and the tunnel was modeled by deactivating elements. The mesh is fully non-structured.

    I also have 10 obs points in the surface, and I ran FePEST and I got the best parameters (zonally constant) for one (out of two) lithologies modeled.

    The thing is that, while the water heads are somewhat acceptable, the inflow in the tunnel is just too damn high for some reason, and it's far away from reality. FEFLOW is giving me that the water budget in the tunnels is like 170 lt/s, but the actual flow is around 100 times less this quantity...  also, 170 lt/s in the tunnels is like almost 60% of the net recharge (!!!!). How is this possible?

    It must be said that the recharge was set by using the In/Out flow top/bottom, by selecting the whole region a value of q=9.75E-9 [m/s], and the topographical area is 30761350 [m2] which is equivalent to 300 lt/s over the whole area.

    The 'seepage face' boundary condition was set in the nodes of the tunnels. On surface, there are some small creeks as well and they were modeled by using the same BC.

    Any comment or advice? I don't know what to do have some reasonable water budgets in the tunnel, there must be something wrong somewhere but I'm unable to detect it. I attach the geometry of the model, so you can see that it's unreasonable to have 60% of the recharge flowing in the tunnel.
  • Re: A lot of questions regarding estimation of K

    Hi, thanks for your reply.

    In fact, the FEFLOW run takes exactly 4 min to finish (steady state, water flow only).

    This FePEST run I was asking for, ended after 130 hours of simulation. (sadly the results weren't satisfactory, due to constraints). The model calls aren't related to the time of simulation in FEFLOW, due to the 4 min don't match with the calculation you just made. It's a different thing.

    And, indeed... by adding pilot points the time required skyrockets.

    Kind regards.
  • A lot of questions regarding estimation of K


    I'm quite new with FEPEST, the thing is that I run the model to estimate calibrated values for Kx, with Ky and Kz tied to this parameter (kx=Ky=Kz). I have also 10 obs points. Only K of only one lithology is being optimized ('Marlstones') spatially, whereas 'Dolomites' is going to have a constant value.. Also, I've added 20 random pilot points in the whole model.

    The thing is that, it's been more than 90 hours running, and the model seems to be unstable, since Phi is going upwards after opti-iteration 7. Why is this? is it normal for FEPEST to run this slow? I attach here some images. [b]Also, this is a FEFLOW model with steady-state flux only. [/b] the FEFLOW model runs in like 1:30 min or something like that (or maybe less).

    In the tutorial there's an example and the model was ready after almost an hour... am I doing something wrong?

    Please any comment is GREATLY appreciated.
  • Re: How to use a surface object to create a group selection?

    Sure, I use Rhinoceros 3D as cad solution and pre-process everything related to geometry.

    The tetgen algorithm is a built-in option within FEFLOW.

    If you have more specific questions don't hesitate to write me.
  • Re: How to use a surface object to create a group selection?


    In my experience, there's nothing wrong or difficult to work with only .stl files in FEFLOW. In fact, in my thesis I only used this kind of file.

    Having said that, I suppose that you have a 'clean' non-manifold surface. Try to close it somehow, and assign region-markers to each enclosed zone. If you're using the tet-gen algorithm, it will generate different groups according to region-markers.
  • Re: Question about budget and Darcy flux plot

    Thanks Peter ;)

    Kind regards
  • Re: Question about budget and Darcy flux plot

    Peter, thank you again!

    1) I generated the DAC file with the data from all the nodes, but when I press the 'stop' button, I still lose the visualization of Darcy's results. Is the DAC file supposed to be opened or something like this?

    2) Yes, now I'm getting appropriate values, I don't know what went wrong before, to be honest. ::)

    Kind regards,

  • Question about budget and Darcy flux plot

    Hello :)

    I have two queries:

    1) Why does the Darcy flux plot (nodal and elemental) become unavailable after stopping the simulation? (red square). Is this supposed this way? How can I have the results of these plots without running over and over again?.

    2)Regarding budgets, when I want to export the results ('rate budge' in 'data' panel) I get only zeroes in the excel file, and it also becomes unavailable when I press 'stop' button, how can I prevent this?

    Thank you in advance!
  • Re: Is there a way to get values of nodes in FEFLOW?


    Thank you Jadinata

    Kind regards