Posted Mon, 29 Nov 2021 07:37:08 GMT by Michael van Til Ramboll
I am looking to implement recharge on a daily timescale in my FEFLOW model. I have a 20-year timeseries that will be uniform for the entire model domain. However, I want to multiply the daily values by a 'paved area coefficient' that I have created using an elemental distribution.

My first problem is assigning daily recharge values (over a 20-year period) to the approximately 100,000 elements in the mesh. I've not yet had success assigning daily timeseries values over such a long period to so many elements. Is there a less computationally-intensive way to assign daily timestep values to so many elements?

My next problem is finding a way to multiply the 'paved area coefficient' contained within my user-defined elemental distribution (which is constant in time) with the daily recharge values. Is this possible within FEFLOW's Equation Editor? I can't seem to find a way to multiply the coefficient at each timestep.

Thanks in advance.
Posted Tue, 14 Dec 2021 15:54:52 GMT by Carlos Andres Rivera Villarreyes Global Product Specialist - FEFLOW
You can link the parameter source/sink or in/out-flow on top/bottom to a mathematical expression (or Python function). The expression will be evaluated before the time step execution, so you can basically modify anything as you want, e.g. using elemental user distributions with potential recharge factors.
There are different ways to introduce the temporal data in FEFLOW, I will recommend you to take a look on

Cheers, Carlos
Posted Wed, 05 Jan 2022 16:09:05 GMT by Michael van Til Ramboll
Hi Carlos,

Ok, so instead of the 'Use Parameter Value' option - selecting elements and applying an expression for each timestep, I can apply the 'Use Mathed Expression' option and it should evaluate the value for each timestep as the model runs?

I've attached a screenshot of the equation I'm currently using. "ED.1" is the elemental user distribution, and "TS.Recharge" is the timeseries with daily recharge values. I assume this gets applied to all elements in the mesh for each timestep when I run the model.

I assume I still need to make sure that the 'In/outflow on top/bottom' parameter has the same amount of time stages as the timeseries file I'm using in the equation?


Posted Tue, 18 Jan 2022 10:12:05 GMT by Carlos Andres Rivera Villarreyes Global Product Specialist - FEFLOW
Yes, FEFLOW Expression Editor will apply the TS function and expression to all the elements. You can easily create IF -THEN statements for cases, where you need to restrict this operation.
The recent FEFLOW versions supports the use of Python function to a set of material properties. You can store a Python function in the Scripting menu in the FEFLOW 7.5 GUI. After right-clicking In/Out flow on/top bottom (context menu), you will see the possibility to connect the function with the material.
Definitively, you have a much higher degree of flexibility with Python compared to MATHED methods.


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