Dear Beatrix,
thank you for the hints. I read the documentation but still I'm
wondering if it is the proper behaviour what I get in the previous
figure. Also, should I expect problems swithching from cartesian to
unstructured grids?
Thank you again,
Lorenzo
On 05.12.2018 13:36, Beatrix Becker wrote:
Dear Lorenzo,
There is a list of run-time parameters on the Dumux website, e.g. for
the 2.12 release: https://dumux.org/doxygen/2.12/a06491.HTML
All run-time parameters are explained there. Does that help you?
Additionally, it is always a good idea to have a look at the code to
understand what it does. Simply grep for something that you are
wondering about, e.g. by typing when you are in the dumux-module folder
grep -r "EnableInitializationIndicator"
The console will print parts of the code, which may be enough to get
some understanding, and additionally you can open the files and read
through the code.
I do not understand your question about the alugrid.cfg file... I
never did anything in particular with it.
Best regards,
Beatrix
Am 05.12.18 um 10:56 vorm. schrieb lc:
Hello,
thanks for the previous answer, it was helpful.
About grid adaptation, I tried but I get strange refinement, as
reported in the figure.
In particular, I don't know how to set this block:
[GridAdapt]
EnableInitializationIndicator = 1
RefineAtDirichletBC = 1
RefineAtFluxBC = 2
MinLevel = 0
MaxLevel = 2
RefineTolerance = 0.05
CoarsenTolerance = 0.001
Also, should I use the alugrid.cfg file? At the moment I don't use.
May you give me some hints please?
Kind regards,
Lorenzo
On 03.12.2018 15:41, Gläser, Dennis wrote:
Hi Lorenzo,
regarding your point (3):
Let us consider the mass balance equation for one of the phases.
Then, for outflow BCs the flux across the boundary is computed by
using the current pressure gradients. For a darcy flux this would
mean -(K*gradP)*normal is evaluated on the boundary. Afterwards, the
flux is turned into a mass flux by multiplying with the mobility and
the density, for which we typically use a simple upwind scheme.
Thus, these values are obtained from inside the domain, which means
that this only works well as long as you really have a flux leaving
the domain. If the sign flips (essentially an inflow boundary),
mobility and density are not defined.
With respect to your question what the difference is: you could
achieve the same thing manually by implementing the above mentioned
stuff into the neumann() function:
But note that especially for cell-centered schemes the outflow BCs
are rather tricky to realize and personally I would try to avoid
them and restrict myself to Neumann and/or Dirichlet BCs where you
actually know what exactly happens.
Best wishes,
Dennis
------------------------------------------------------------------------
*Von:* Dumux <[email protected]> im Auftrag
von lc <[email protected]>
*Gesendet:* Montag, 3. Dezember 2018 12:37:19
*An:* [email protected]
*Betreff:* [DuMuX] on IMPES, grid adaptation and BCs
Hello,
I have the following questions:
1) Is it possible to run IMPES algorithm in sequential (not implicit)
mode without considering capillarity forces (pressure)?
2) Is it possible to do some sort of grid adaptation, for example
locally refine the (unstructrured) mesh where the water saturation
front
becomes steeper? If yes, how, is there any example?
3) What actually the Outflow BC does? What is the difference with
Neumann?
Thank you very much!
Kind regards,
Lorenzo
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--
*******************************************************
Beatrix Becker
Department of Hydromechanics and Modelling of Hydrosystems (LH2)
Institute for Modelling Hydraulic and Environmental Systems (IWS), University
of Stuttgart
www.hydrosys.uni-stuttgart.de
email:[email protected]
Pfaffenwaldring 61
70569 Stuttgart
Tel.: ++49 711 / 685-60500
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