for the vertex-centered finite volume discretization, the relevant
position for calculating the gradient is *not* the position of the
center of the *sub*-control volume, but the center of the whole
control volume.
Since this patch changes the gradients of all VCFV simulations that
use twopoint gradients, quite a few new reference solutions are
required by this PR. I've looked at all of them manually and made sure
that they look reasonable. (The PR also includes a new reference
solution for the test for the adaptive finger problem -- which uses
ECFV -- but that's because the grid refinement seems to be quite
sensitive to the solution proceedure for that problem, not because
there's any difference in the solutions that can be noticed visually.)
note that all simulations that use element centered finite volume
discretization because there sub-control volumes are identical to full
control volumes. In particular, ebos -- and by extension `flow_ebos`
-- is unaffected because it does not even use that code.
as a side effect, two-point gradients are now used by default for the
vertex-centered finite volume discretization. (because P1-FE gradients
require the FE shape functions and those are provided by
dune-localfunctions.)
as a consequence, this triggered an update of quite a few reference
solutions: the differences are measurable, but as far as I can see,
the results are compareable. also, this commit regresses the
performance of the test for the reservoir problem with the vertex
centered finite volume scheme a bit. While I would not bet a house on
the reason, I'm pretty sure that this is caused by the switch from P1
FE gradients to two-point ones.
Note that even though I'm the author of this patch, it shamelessly
rips off substantial parts of the @dr-robertk's patch:
https://github.com/OPM/ewoms/pull/69
- start with an initial "do nothing" episode of 100 days to get
hydrostatic conditions.
- after that, produce oil and inject water for 900 days. (thereafter
the reservoir will be empty.)
- make the problem work with element centered FV discretizations. this
requires to make the width of the injection/production areas at
least one cell wide. This is achieved by using the new "WellWidth"
property which specifies the with of wells as a factor of the total
domain width.
- make the problem work with fully compositional models. This implied
to calculate the full composition for the fluid states which specify
the initial condition and the thermodynamic state at the wells.
- add tests and reference solutions for any combination of the {ECFV,
VCFV} discretizations and the {black-oil, NCP} models.
