Silverbrook

Thanks Bjorn!

Is export of the rate or period budgets for mass the correct way to assess the imbalance in the mass budget (rather than fluid budget) in FEFLOW 7.0? I seem to be getting very large imbalances (up to 50-100%) and wondered whether I was exporting the wrong data to assess this? If not, then what is the best way to address this imbalance? I am using automatic time stepping - so that leaves refining meshes (either laterally or by layering) around steeper concentration gradients? I have convergent flow fields (pumping from within a stationary plume) rather than the more common in literature source to receptor conceptual model - so presumably a smaller dispersivity would make more sense? Might this make achieving a good mass balance problematic?

So would it be right to say that when applying the error norm to the max error that it is essentially working to try and solve by ensuring that any areas that are numerically problematic are focused on during the solving routine?

Thanks Pete. I found a problem with a boundary condition that was causing the issues.

Out of interest, and for future reference, what does the 0.1 [*1e-3] error tolerance represent, and under what circumstances would we consider altering it?

Hello,

I'm not sure what this should be set at. The default value is 0.1 [*1e-3]. What justification is there for changing this from the default in a model that is not converging?

Thank you,

SB

Hi,

I'm aware that there are certain parameter distributions and combinations of boundary conditions that can cause instabilities and convergence issues, but if I am unable to locate any problem areas, or unable to sacrifice some specific part of the model design, is there a systematic approach to altering solver types & settings in order to improve convergence? I expect this will most likely increasing model run time!

Thanks,

SB

Is it possible to enter transient reference data (i.e. observed head values distributed over time) so that they can be compared with the modelled hydrographs from within FEFLOW 5.4/6.0? Or do I have to export the modelled hydrograph data and plot it in another program to compare with my observed data?

Thanks,

SB

Hi,

What is the best way to add a series of new wells into a model with an existing mesh so that they are located on new nodes matching the well's 'true' coordinates? The mesh has already been used extensively in its current form, and has many complex boundary conditions and property distributions. Unfortunately it is far too coarse in the vicinity of the new well field we are about to add, so we need to find a way to adapt the current mesh.

One option could be to manually refine the mesh around images of the well locations on an imported map, then use the move node function + F2 to force the node to be equal to the exact well location. However, we would rather not move nodes as this will slightly alter the z-elevations within the adjacent elements.

Is there a way that I can import a well as a new node and force the program to refine the element in which it would be located? Or is there another way to do this?

We have FEFLOW 5.4 and 6.0

Thanks,

SB

Any ideas?

Hi,

There was a list of all the FEFLOW file types and how their content should be formatted that I used to have. In the past I was able to find this with a simple google search but I can't locate it anymore. Where abouts can I find it? I just want a quick reference list for the format for the file content for all the different file types that FEFLOW uses (e.g. what to enter and how to arrange it so that a .pow file will function correctly).

Thanks,

SB