Hi Patrick,
On 04/23/2018 03:42 PM, Timo wrote:
Hi Patrick,
welcome to the Dumux mailing list.
If you are just starting Dumux, is there any reason you are doing so
with a very outdated version? The current dumux version is 2.12 and
works with dune 2.5 or dune 2.6.
I'm not too familiar with the TwoPAdapter, but it is meant to be an
adapter for a two-phase model to fullfill the interface of the more
general mpnc model.
The comments most probably are related to how this law is used in the
volume variables (see mpnc model volumevariables.hh:200). As the mpnc
model is quite general it may be hard to understand
because of many abstractions. For a two-phase system this does what
you expected i.e. pc = pn – pw.
Just a more detailed explanation since I started writing it. Look at
mpncvolumevariables.hh lines 161ff. Assuming wPhaseIdx to be 0 and
nPhaseIdx to be 1, we have that the vector capPress = {-pc, 0}. Assuming
the mostWettingFirst formulation, the first pressure is set to
p0 = pw - capPress[0] + capPress[0] = pw - (-pc) + (-pc) = pw
and the second to
p1 = pw - capPress[0] + capPress[1] = pw - (-pc) + 0 = pw + pc
which coincides with pn in your definition of pc.
Kind regards
Bernd
Which model are you trying to use? Do you have more than two phases?
If yes, how many?
If not, simply use a two-phase model and the Brooks-Corey material
law. There is also a three phase VanGenuchten model implemented.
But you would need to write a ThreePAdapter to use it with the mpnc
model. There is currently no Brooks-Corey law for more than 2 phases
implemented,
but it should be easy to add if you know what it looks like for your
system.
I might be easier to help if you describe which problem you are trying
to solve with Dumux (phases, components, miscibility, wettability, ...).
Best wishes
Timo
On 23.04.2018 15:02, [email protected] wrote:
Hello everyone,
I am new to the Dumux community and therefore, also after completing
the tutorials, still quite unexperienced.
Since over one week I am focusing on material laws and capillary
pressure especially, but there are two questions
for which I cant find any answers. The versions I am working with
right now is dune 2.3 and dumux 2.7
I am working with the Brooks-Corey material law and call it via the
TwoPAdapter („2padapter.hh“), but there are two things I dont
understand so far:
1. In function static void capillaryPressures(): Contrary to the
commentary lines, the nonwetting phase gets nothing added and the
capillary pressure is actually
subtracted from the pressure of the wetting phase, what is the
purpose of that? As far as I know, the capillary pressure is defined
as the difference between
the pressures from nonwetting and wetting phase i.e. pc = pn – pw
The passage of code I am talking about is lines 61-65 in
dumux/material/fluidmatrixinteractions/mp/2padapter.hh:
„
l. 61: // non-wetting phase gets the capillary pressure added
l. 62: values[nPhaseIdx] = 0;
l. 63:
l. 64: // wetting phase does not get anything added
l. 65: values[wPhaseIdx] = - TwoPLaw::pc(params,
state.saturation(wPhaseIdx));
„
2. The description in file 2padater.hh states, that the TwoPAdapter
can be used to apply Brooks-Corey to M-phase fluid systems, but I
dont get it how that can be accomplished
since the number of phases is defined inside class TwoPAdapter as 2
(l. 51 „enum { numPhases = 2};“). It is also referred to another
file called „MpBrooksCoreyMaterialParams“ (l. 42)
but I cant find the respective file anywhere. On the other hand I
found in the same folder „mplinearmaterial.hh“ and
„mplinearmaterialparams.hh“ which make the linear material law
applicable for multiple phases. Is it possible that multiphase
Brooks-Corey was not fully implemented yet in dumux 2.7? If yes, what
are the alternatives? I was thinking about defining
temporary fluidsystem, each containing two phases with decreasing
wettability and then calling the TwoPAdapter for those systems, would
that be possible?
Thanks already for any support, I appreciate any advice!
Best Regards
Patrick
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Bernd Flemisch phone: +49 711 685 69162
IWS, Universität Stuttgart fax: +49 711 685 60430
Pfaffenwaldring 61 email: [email protected]
D-70569 Stuttgart url: www.hydrosys.uni-stuttgart.de
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