Thanks for your interest in FiPy On Mon, Oct 16, 2017 at 6:16 PM, F Hssn <fhs...@gmail.com> wrote: > > So my questions are: > > - Does fipy handle anisotropic unstructured meshes without any > problem? (I'm specifically looking to use bamg for 2D mesh adaptation > based on interpolation error reduction/equidistribution)
What is an anisotropic mesh? FiPy does "handle" unstructured meshes in that the problem will solve, however, the accuracy decreases as the non-orthogonality and non-conjunctionality increases (as you pointed out). There has been an attempt to implement terms to correct for the non-orthogonality, see https://github.com/usnistgov/fipy/blob/develop/fipy/terms/diffusionTermCorrection.py and https://github.com/usnistgov/fipy/blob/develop/fipy/terms/diffusionTermNoCorrection.py You might want to try playing with the corrected diffusion term to see how well it works. I can't find any examples of its use though. See also - https://www.mail-archive.com/fipy@nist.gov/msg03758.html - https://www.mail-archive.com/fipy@nist.gov/msg03757.html - https://www.mail-archive.com/fipy@nist.gov/msg03765.html > - If not, does fipy provide (or provide a way to implement) MPFA > (multi-point flux approximation) or some other non-classical scheme > (like HMM) that allows anisotropic unstructured meshes (as discussed > in the Drioniou paper [1]) ? I don't think I can easily answer that without a great deal of work, but I did skim over the Drioniou paper, https://arxiv.org/pdf/1407.1567.pdf. I can't foresee all the issues with implementing the various schemes but one that does come to mind is having to use neighbor's neighbor values to compute fluxes, which I think these schemes require. It would require a lot of changes to FiPy to set that up efficiently. However, I will certainly keep this paper on my list of items to research further. Thanks for highlighting it. > - Or, does fipy allow any other way to make vertex-centered control > volume calculation that can take into account anisotropy and can make > sure there are no control volume overlaps (and as a result, the > coefficients stay positive, and monotonicity is maintained, and none > of the nice properties are violated) ? No, FiPy is definitely not set up for vertex centered. The above cell-centered approach is the way to go. -- Daniel Wheeler _______________________________________________ fipy mailing list fipy@nist.gov http://www.ctcms.nist.gov/fipy [ NIST internal ONLY: https://email.nist.gov/mailman/listinfo/fipy ]
