Hi Lorenzo,
does it get better if you lower the CFL factor?
Timo
On 19.12.18 11:10, lc wrote:
Hello,
I observed an unexpected behaviour for which I'd like to ask your
help. In the attached figure you can see a snapshot of the solution.
In both the contour and in the line chart you may notice some spurious
"background noize". I noticed that such effects starts at a certain
time from the right (outlet) boundary and then increase entity and
becomes as you see.
I think it could be due to the fact that my initial condition is not
consistent with boundary condition but it is just an hypothesis. I
enclose the file where you can read the IC.
I would like to ask if you ever noticed some similar effect and
possible ways to fix it.
About fixing, I had 2 ideas:
1) to add an "epsilon" premultiplying the wetting phase saturation
term which I expect should dump it out; (how to do it?)
2) to add a cut-off function to the initial.
Is there anything like this availble in DuMux?
Or should I use the regularization of the saturation, which now I
don't use?
I use DuMux 2.12.
Thank you,
Lorenzo
On 17.12.2018 16:43, Dennis Gläser wrote:
Hi Lorenzo,
sorry, I didn't realize that you were using Dumux2.12. In this case,
forget my last mail. In the future, please try to reply to previous
mails of the conversation so that they can be read (I am sure you
mentioned somewhere that you were using 2.12).
In DuMuX2.12 there was no support for a spatially varying definition
of the wetting/non-wetting phase. Using 2.12 you can obtain the
wetting/non-wetting phase mass conservation equation indices from the
Indices class via Indices::contiWEqIdx and Indices::contiNEqIdx.
Best wishes,
Dennis
On 17.12.18 14:33, Dennis Gläser wrote:
Hi Lorenzo,
you have to distinguish between primary variable indices and
equation indices. Your equations (2p model) are always the mass
balances of the two phases, independent of you choice of primary
variables. In 2p/implicit/incompressible/problem.hh you have an
example on how to adress the equation indices:
using Indices = typename GetPropType<TypeTag,
Properties::ModelTraits>::Indices;
enum {
pressureH2OIdx = Indices::pressureIdx,
saturationDNAPLIdx = Indices::saturationIdx,
contiDNAPLEqIdx = Indices::conti0EqIdx + FluidSystem::comp1Idx,
waterPhaseIdx = FluidSystem::phase0Idx,
dnaplPhaseIdx = FluidSystem::phase1Idx
};
In this case DNAPL is the non-wetting phase. The equation index is
adressed via Indices::conti0EqIdx (which gives the index of the
first mass balance equation within your vector of equations) plus
the component index of the first component in the fluid system.
So, in order to determine the right equation indices for the phases
of your fluid system within the equation vector, you need to use
conti0EqIdx and then add the index of the respective components of
your fluid system.
I am sorry if my last answer wasn't adressing the right issue. Also,
it seems that I wrote the default formulation is pw-sn. That is
wrong, the default formulation is p0s1, meaning that the pressure
primary variable is associated with the phase with index 0 of your
fluid system, and the saturation variable is associated with the
phase with index 1 of your fluid system. You can change this to
p1s0, if desired.
However, from the indices you can only obtain pressureIdx or
saturationIdx (there is no such thing as Indice::snIdx anymore), as
DuMuX can not decide for you which phase is the wetting phase or
which the non-wetting phase. You tell DuMux which phase is the
wetting phase by implementing the function wettingPhase() or
wettingPhaseAtPos() in your spatial parameters.
I hope this helps you!
Best wishes,
Dennis
On 17.12.18 13:51, lc wrote:
Hello,
On 02.11.2018 10:45, Dennis Gläser wrote:
per default, the formulation for the 2p model is pw-sn. That means
your primary variables are the water pressure and the non-wetting
phase saturation (in your case oil I assume). Therefore,
Indices::swIdx does not exists as it is not part of your primary
variables.
then, if physically I have a water (wetting) phase injection at
inlet (which traduces into a mass flow rate) how can I impose it in
2p implicit model?
Best regards,
Lorenzo
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Timo Koch phone: +49 711 685 64676
IWS, Universität Stuttgart fax: +49 711 685 60430
Pfaffenwaldring 61 email: timo.k...@iws.uni-stuttgart.de
D-70569 Stuttgart url: www.hydrosys.uni-stuttgart.de
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