Nernst-Planck module in recent versions

[majin....@gmail.com]

Dear Glenn,

I'm modelling transport in clay rocks and would like to use the Nernst-Planck implementation in more recent PLFOTRAN versions. I notice that the installation (e.g., v7.0) comes with "transport_np.F90", and I can use "NERNST_PLANCK" keyword under OPTIONS without any problem/warnings. 

There seemed to be a small bug on tortuosity (scalar instead of tensor, Line 85 & 86), after fixing that it seems to give reasonable results, so I'm trying to benchmark it against Alt-Epping et al., 2015 and 2018. The results are fairly close, but there seems to be some discrepancy at the boundary with the other models when using ZERO_GRADIENT or NEUMANN for transport BC.

I understand that the NERNST_PLANCK module is not in the official documentation, but may I ask if it is somehow still maintained or tested? 

Many thanks,

Jin 

[Hammond, Glenn E]

Jin,

I apologize for the delayed response. 

The NERNST_PLANCK code continues to be maintained, as we run several regression tests specifically covering its functionality. However, please note that these tests only verify whether the implementation has changed; they do not confirm the accuracy of the underlying physics. All verification of the physics was managed by the original authors.

Glenn

From: pflotra...@googlegroups.com <pflotra...@googlegroups.com> on behalf of majin....@gmail.com <majin....@gmail.com>
Date: Monday, June 1, 2026 at 9:04 AM
To: pflotran-users <pflotra...@googlegroups.com>
Subject: [pflotran-users: 8793] Nernst-Planck module in recent versions

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