Dear Sebastian,
for CP-grids it might happen that the centroid is located out of the
cell such that the currently implemented
transmissibility calculation yields negative values.
Did you check if all the transmissibility calculated with the functions
in the following header
https://git.iws.uni-stuttgart.de/dumux-repositories/dumux/-/blob/master/dumux/discretization/cellcentered/tpfa/computetransmissibility.hh
are positive?
I guess you will observe negative values. There are two solutions to
overcome this
1. Try to use another cell center instead of the centroid.
2. Try to use the absolute value of the transmissibility (corresponds to
switching the normal vector of the corresponding face)
I hope this solves your problem.
Best regards,
Martin
On 02.09.21 18:15, Alexander Sebastian Hogeweg wrote:
Hello everyone,
I am facing a problem during the simulation of an underground gas
storage scenario. The used grid is a cornerpoint-grid with a
heterogeneous distribution of permeability and porosity. Additionally,
the structure contains a fault connecting a lower part of the
formation. The used fluid model is 2pnc (h2on2o2), and the
initialization is based on the example 2p_cornerpoint (hydrostatic
pressure and pores fully water-saturated). At the top and bottom of
the structure, Neumann (no-flow) boundaries are defined (Dirichlet at
the sides with initial). In the present status, the molecular
diffusion is deactivated, and additionally, the centroid cell center
location is used.
After the initialization (looks all right), the pressure in some cells
of the lower part increases while neighboring grid blocks show a lower
pressure. Attached you can find some images showing the problem (Image
1 and 3: t=0; Image 2 and 4: t =6000s (timestep 8) and the problem
file. Other (more conforming) cornerpoint-grids do not show this
behavior.
Overall, I would like to know if somebody else observed a similar
situation and could help me with the problem.
I appreciate any help you can provide, and please let me know if you
need further information.
Best Regards,
Sebastian
Dumux Version: 3.4
Model: 2pnc
Grid type: Cornerpoint
Fluid system: h2on2o2.hh
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