Björn Kaiser

The Richards equation is reduced to the Darcy equation within domains where the system is saturated. The Darcy flux in the Data Panel can be used to plot the vector in both saturated and unsaturated domains.

Adam, I made some further checks. Could you please provide a part (snippet) of you code? I am interested in the line where you use the API function IfmGetElementalRefDistrName. Please also provide the lines where you initialize the variables used for the API function. Thank you in advance.

Thanks for the note Adam. It seems there is a bug related with UTF-8. We will fix it as soon as possible. In the meantime, I suggest to use ASCII-conform characters.

If you do not use any constraints imposed on the wells I assume you a priori the total amount of water over time to be extracted. To pre-process you data I suggest to generate a new time-series representing the total amount of water. Then you may consider the time-series in your expression and multiply it by 0.7. Alternatively, you could make the multiplication during the preparation of the time-series. In the latter case you do not need any expression.

What kind of Boundary Condition did you assign at the bottom of your model to represent the inflow?

The degree of approximation should be related with the degree of balance accuracy you are interested in. For example, if the free convective system is superposed by forced convective processes (e.g. triggered by pumping to keep a specific threshold of the primary variable(s)), then the required amount of water may change between these approximations. This may be attributed to the fact that density may change the volume of water.

Indeed, there is no "guideline" which states which degree of approximation should be used for which case. A "guideline" is ventured, because the different cases may vary drastically. In other words, each numerical model is unique. Accordingly, if your system is characterized by sharp gradients in density, then you may try different degrees of approximations.

Beside the spatial discretization, the temporal discretization may also play an important role. If you simulate density-driven flow phenomena, you may try to constraint the time-step size in addition to the automatic predictor-corrector time-stepping scheme by adopting a [b]growth factor between subsequent time-steps[/b] and/or a [b]maximum time-step size[/b]. In this context, a stricter [b]error tolerance[/b] and/or [b]error norm[/b] may also help to reduce the imbalance.

Thanks Christian. I made a test with approximately the number of nodes/elements you indicated. The runtime corresponded approximately to the time of a coffee break. My coffee breaks are usually not long (minute scale). Could you please provide more details about your computer (CPU, memory). If you aggree we can also continue this request in the FEFLOW support.

You need to generate one or more ASCII-based files with the extension *.pow. Here is an example how the file format may look:

[font=courier][color=blue]
# ID1
! Comment line for time series 1
! ...
x1 y1
x2 y2
...
xm ym
END
# ID2
! Comment line for time series 2
! ...
x1 y1
x2 y2
...
xn yn
END
# IDn
! Comment line for time series n
! ...
x1 y1
x2 y2
...
xo yo
END
END
[/color][/font]

If you are new with FEFLOW, I suggest to go through the FEFLOW Introductory Tutorial: https://www.mikepoweredbydhi.com/download/product-documentation

This exercise called Friedrichshagen guides you step-by-step through the Graphical User Interface (GUI) of FEFLOW by setting up a 3D groundwater flow and mass transport model including wells. I also shows you how to work with time-dependent data as such as observation points.

You may download corresponding Demo data from our website: https://www.mikepoweredbydhi.com/download/mike-2016

Hi Eduardo, at the moment this function does not exist. I added this function to the FEFLOW wish list for possible future developments.

Which Node Selection Mode did you use? [b]Select by node number[/b] or [b]Select by nearest node(s)[/b]?