Hi Etienne,
sorry to get back to you so late.
1. The residual evaluation is done element-wise. On each element,
secondary variables are calculated from the primary ones by using the
material law defined on the subcontrol volume. If the parameters are
defined element-wise like in your example, it uses different parameters
for the different subcontrol volumes. We are disregarding the possible
jump in saturation.
The right way to treat this situation would be by means of an
appropriate interface condition,
http://link.springer.com/content/pdf/10.1007%2F3-540-45467-5_4.pdf
We still need to implement this.
If your model setup allows it, you can define your material parameters
control-volume-wise. This would get you out of this problem, but has its
own ones -> 2.
We are not satisfied about this current situation and are working on an
improvement.
2. Thank you for the hint. I was not really aware of this fact. I am not
sure it this plays such a big role for large-scale simulations with
usually large element sizes. Nevertheless, we would heavily welcome an
implementation of a corresponding Riemann solver to solve this issue.
Alternatively, this sounds like a good student thesis to me.
Kind regards
Bernd
On 03/22/2016 04:01 PM, Etienne Ahusborde wrote:
Hi Bernd,
You will find in the enclosed file two questions concerning this point.
Best regards
Etienne
Le 21/03/2016 16:57, Bernd Flemisch a écrit :
Hi Etienne,
yes, this is what we do. Can you give more details on why/when this
is problematic?
Kind regards
Bernd
On 03/21/2016 10:48 AM, Etienne Ahusborde wrote:
Dear DuMuX Community,
With my colleagues, we would like to know how Dumux treats the
computation of the convective flux at the interface of two
heterogeneous
media for the implicit scheme.
It seems that for the absolute permeability, an harmonic mean is
used while for the mobility, a weighted upwinding is used (with by
default
mobilityUpwindWeight_=1 in
dumux/imlicit/common/implicitdarcyfluxvariables.hh).
We wonder if an other specific treatment is performed since
upwinding can produce non-physical solutions.
Thanks in advance for precisions.
Best regards
Etienne
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_______________________________________________________________
Bernd Flemisch phone: +49 711 685 69162
IWS, Universität Stuttgart fax: +49 711 685 60430
Pfaffenwaldring 61 email: be...@iws.uni-stuttgart.de
D-70569 Stuttgart url: www.hydrosys.uni-stuttgart.de
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