SNOW AND SNOW2 NOT GIVING THE SAME VALUE OF PORES, THROATS AND PERMEABILITY

[JahanzebTariq]

DEAR PROFESSOR, I have been able to run the code and extract network through open PNM and porespy , but the issue I face is that I am not getting the same number of throats, pores and most importantly the permeability value. I humbly request you to please solve my issue.
Thank you

[jgostick]

Yes, that's why we called it snow2, since there are some differences in the code. How different are your permeability values?

[JahanzebTariq]

@ma-sadeghi .. and sir 1 more thing I wanted to point out is SNOW2 algorithm is giving me more numbers of pores and throats than SNOW.
Further I wanted to ask that I am not being able to use spheres and cylinders as the message pops of throat diameter being greater than the pore diameter... any possible solution on this..?

[ma-sadeghi]

@JahanzebTariq Please do one more modification: try "pore.inscribed_diameter" instead of "pore.equivalent_diameter".

[JahanzebTariq]

@ma-sadeghi ... OMG sir.. You are so great.. I got 721.3061 mD after trying "pore.inscribed_diameter" instead of "pore.equivalent_diameter".. This is more closer to the experimental result.

[JahanzebTariq]

@ma-sadeghi .. Excuse me sir.. could you kindly tell me the reason behind switching the diameters..
Thank you

[jgostick]

It's in the name: Inscribed diameter is the diameter of a sphere fits entirely withing the pore region, whereas equivalent diameter is the diameter of a spheres with the same volume as the region. Inscribed will always be smaller.

[jgostick]

Also, I will point you to this script, which is part of our test suite, that ensures the extracted network gives correct Permeability and Formation Factor values for Berea:

[JahanzebTariq]

Dear Professor I also took help from this script.. I am a MS student and currently in my research phase so I am trying to replicate a paper whose code was the first one. The second is my code.. please could you check from the portion from where I applied the snow2 algorithm.

from previous paper

net = ps.networks.snow(im=im, voxel_size=resolution)
h = pn.check_network_health()
op.topotools.trim(network=pn, pores=h['trim_pores'])
h = pn.check_network_health()
print(h)

I changed

snow = ps.networks.snow2(im, voxel_size=resolution)
pn = op.io.network_from_porespy(snow.network)

h = op.utils.check_network_health(pn)
op.topotools.trim(network=pn, pores=h['disconnected_pores'])
h = op.utils.check_network_health(pn)
print(h)

[JahanzebTariq]

when I pass these arguments in the Snow2 algorithm I get on x direction of permeability

snow = ps.networks.snow2(im, voxel_size=data['resolution'], boundary_width=[3, 0, 0], accuracy='standard')

This piece of code is taken from your recommended script.

[jgostick]

I'm not sure what you're question is. Putting boundary_width of [3, 0, 0] means that boundary pores are only on the x faces. If you want to do the other directions you can put boundary pores there too. Of course you can also put no boundary pores and just use real pores on the faces for assigning boundary conditions. Ultimately, the user is responsible for making these decisions.

[JahanzebTariq]

@jgostick .. and sir please show how can I remove the boundary pores..?

[JahanzebTariq]

There has been alot of change in the SNOW algorithm particularly naming, which is confusing me a lot, making me fearful of making mistakes..