Two issues about Drainage and InvasionPercolation in version 3.10

[Aneurinsky]

Hi, The openpnm open source package has enhanced my understanding of two-phase flow at the pore scale. In the study of the new version, there are two questions that bother me, and I still need your answers:

（1）
In version 3.10, the Drainage algorithm is selected and the calculation is completed, and the file is saved using project_to_vtk, and the program reports an error:

Similarly, when the InvasionPercolation algorithm is selected, an error will also appear when saving the file with project_to_vtk:

（2）
When applying the Drainage algorithm, the intrusion phase is usually indicated, so is there a default defense phase? If so, what is this defense phase? If not, was the initial state of the network dry or vacuum?

Similarly, for the InvasionPercolation algorithm, if the defense phase is not specified, what is the default defense phase? In RelativePermeability.py, set the defense phase to the default value, or to air, the calculation result is the same? I understand the following statement, the air is not set as a defense phase, I don't know if this understanding is correct?

`air = op.phase.Air(network=pn,name='air')
air['pore.surface_tension'] = 0.072
air['pore.contact_angle'] = 180.0
air.add_model_collection(op.models.collections.phase.air)
air.add_model_collection(op.models.collections.physics.basic)
air.regenerate_models()

water = op.phase.Water(network=pn,name='water')
water.add_model_collection(op.models.collections.phase.water)
water.add_model_collection(op.models.collections.physics.basic)
water.regenerate_models()

DRN = op.algorithms.Drainage(network=pn,phase=water)
DRN.set_inlet_BC(pores=pn.pores('top'))
DRN.run()`

Thank you again for your patience in reading my question and look forward to your reply, thank you！

[jgostick]

Hi @Aneurinsky
The first issue you mention seems like a bug. The file io function is looking for an attribute on the algorithm that is not there. I will investigate and open an issue asap.

To answer your second question(s) about the defending phase, during quasi-static invasions (slow), the defending phase properties do not impact the displacement since there is no viscous effects so there is no need to specific a defending phase. However, trapping can still occur so if you specify 'outlets' then the algorithm will check to see which defending phase pores are no longer connected to the outlets and mark them as trapped. If you don't specify outlets then the algorithm assumes that trapping does not occur, which is equivalent to assuming the defending phase is a vacuum, like in mercury porosimetry.

[JahanzebTariq]

@jgostick .. I'm also having the same issue

[jgostick]

Just pushed a fix. Will merge into dev today. There is one other branch which I would like to also merge into the dev before creating a new release. This other branch is also almost ready, so I expect to have a new "patch" release this weeks, like OpenPNM 3.1.2.

[JahanzebTariq]

I am still getting this issue please tell me if this has been resolved or not..? thank you

[jgostick]

The MacOS builds are failing, so I was waiting to figure that out before merge. The patch is available on the dev branch if you are able to use that. It requires pulling the source code from Github, installing using pip install -e /path/to/cloned/repo, then you 'checkout' whichever branch you like.

[JahanzebTariq]

professor i'm not that good at these things.. approximately how long is it going to take for the bug to be completely fixed at your end?

[JahanzebTariq]

Greeting @jgostick .. SIr I've extracted the percolation pathways and want to visualize them in paraview..

but this issue has not been resolved yet..

please address this issue as soon as possible. I would be very grateful for this.. thank you in advance

[JahanzebTariq]

@jgostick... would you please tell me in a little more detail how to do it.. My sincere apologies.. but if you guide me a little more I'll be able to get through nicely.. please do reply

[jgostick]

I'm sorry, I should have checked my suggestion first. I have now confirmed that the following will work:

drn.settings['quantity'] = 'throat.invasion_pressure'
drn.soln = {'throat.invasion_pressure': drn['throat.invasion_pressure']}

[JahanzebTariq]

@jgostick ... sir should I go with this one or should I do the dev version?

[JahanzebTariq]

@jgostick .. sir did you tell me the solution to this issue? please do confirm

[JahanzebTariq]

@jgostick .. did what you said but still the error remains

sorry to be such a pain but please do guide me if i am wrong.. thank you