Comment 11 for bug 1362090

> Try imposing velocities to the boundaries of the undrained sample and see if the
> results are consistent in terms of pressure changes.

I rewrote the script. It is now taking 8 minutes for preparing and 2 minutes for final calc. The script saves the model after preparation. So you can set load = True at the beginning of the script to load prepared sample.

changes:
Triax engine is deactivated after preparation steps and velocity of top boundary is imposed, so that the sample is compressed. In the undrained case I get the following result:

Running script pfv-bug-cell-pressure-too-low.py
set fluid bulk modulus to: 2.000000e+09
Starting calculation, number of steps: 100000
p: -0.0 /poro: 48.147175
p: 77.3254702635 /poro: 47.5619234375
p: 128.265866485 /poro: 46.971240625
p: 141.818936358 /poro: 46.3730234375
p: 190.076801101 /poro: 45.7726046875
p: 256.087922324 /poro: 45.163634375
p: 286.638303292 /poro: 44.5447875
p: 336.686906526 /poro: 43.9271546875
p: 370.445026634 /poro: 43.3041359375
p: -246.733682291 /poro: 42.6770140625

If I uncomment line 145: flow.boundaryUseMaxMin=[0,0,0,0,0,0] triangulation is not working correctly...

Running script pfv-bug-cell-pressure-too-low.py
set fluid bulk modulus to: 2.000000e+09
Starting calculation, number of steps: 100000
6 : Vh==NULL!! id=6 Point=0.000512399 0.00124487 0.00125213 rad=3.15073e-05
7 : Vh==NULL!! id=7 Point=0.000587947 0.000954619 0.000983527 rad=0.000124813
8 : Vh==NULL!! id=8 Point=0.00146642 0.000434536 0.00102062 rad=7.286e-05
9 : Vh==NULL!! id=9 Point=0.00151061 0.0011991 0.000915917 rad=9.27561e-05
...
...
279 : Vh==NULL!! id=279 Point=0.000526466 0.000269253 0.00137925 rad=5.56929e-05
280 : Vh==NULL!! id=280 Point=0.000373563 0.000806535 0.000942971 rad=8.59516e-05
281 : Vh==NULL!! id=281 Point=0.000918819 0.00104285 0.00064448 rad=9.2951e-05
282 : Vh==NULL!! id=282 Point=0.000928043 0.0006173 0.000905637 rad=0.000119065
AREA <= 0!!
AREA <= 0!!
AREA <= 0!!
AREA <= 0!!
AREA <= 0!!
AREA <= 0!!
AREA <= 0!!
AREA <= 0!!
p: nan /poro: 48.147175
...

It seems, that all cells get zero volume with each triangulation step.

c