Verification & Validation

This section separates two different kinds of evidence used in voids:

• Verification: benchmarks against software references, manufactured cases, or controlled numerical workflows
• Validation: benchmarks against experimental data

That distinction matters. A software cross-check can show that voids is numerically consistent with a reference implementation, while an experimental comparison asks whether the present workflow predicts a measured physical quantity closely enough for the intended scientific use.

Current Structure

Verification

The software-verification studies live under Verification:

• OpenPNM extracted-network cross-check
• External pnextract / pnflow benchmark
• XLB direct-image permeability benchmark
• DRP-443 fracture-network verification overview
• DRP-10 Estaillades verification overview

Validation

The experimental-validation studies live under Validation:

• DRP-317 sandstone validation overview
• DRP-317 Parker notebook report
• DRP-317 Kirby notebook report
• DRP-317 Bandera Brown notebook report
• DRP-317 Berea Sister Gray notebook report
• DRP-317 Berea Upper Gray notebook report
• DRP-317 Berea notebook report
• DRP-317 Castlegate notebook report
• DRP-317 Buff Berea notebook report
• DRP-317 Leopard notebook report
• DRP-317 Bentheimer notebook report
• DRP-317 Bandera Gray notebook report

What Each Side Answers

Category	Typical reference	Main question	Expected agreement
Verification	OpenPNM, pnflow, XLB/LBM, OpenFOAM-based paper references, manufactured cases	Is the implementation consistent with a software or numerical reference?	Exact to moderate, depending on shared assumptions
Validation	Experimental porosity and permeability data	Does the current workflow predict the measured physical response closely enough?	Case-dependent; mismatch often reflects extraction and constitutive-model limits

DRP-317 Source Citations

The current validation set uses:

• Dataset: Neumann, R., ANDREETA, M., Lucas-Oliveira, E. (2020, October 7). 11 Sandstones: raw, filtered and segmented data [Dataset]. Digital Porous Media Portal. https://www.doi.org/10.17612/f4h1-w124
• Experimental reference paper: Neumann, R. F., Barsi-Andreeta, M., Lucas-Oliveira, E., Barbalho, H., Trevizan, W. A., Bonagamba, T. J., & Steiner, M. B. (2021). High accuracy capillary network representation in digital rock reveals permeability scaling functions. Scientific Reports, 11, 11370. https://doi.org/10.1038/s41598-021-90090-0

The reproducible software-verification notebook artifacts are:

• notebooks/12_mwe_synthetic_volume_openpnm_benchmark.ipynb
• notebooks/15_mwe_external_pnflow_benchmark.ipynb
• notebooks/13_mwe_synthetic_volume_xlb_benchmark.ipynb
• notebooks/29_mwe_drp443_ifn_raw_porosity_perm.ipynb
• notebooks/30_mwe_drp443_dilatedifn_raw_porosity_perm.ipynb
• notebooks/31_mwe_drp10_estaillades_raw_porosity_perm.ipynb