23  Elmer Multiphysics

Elmer is a multiphysics finite element method (FEM) solver mainly developed by CSC and maintained at GitHub. Several resources can be found in is official webpage and in the community portal and in the forum. There is also an YouTube channel with several tutorials and illustration of the package capabilities.

The goal of this page is not to supersede the documentation, but to make it (partially) available as a webpage where search and navigation become more intuitive. Notice that this will be fed according to my personal projects and learning, so any contribution to accelerate the process is welcome. Here you find a user-guide-style page with more details are provided below in the selected notes of Elmer documentation.

23.1 Quick answers

  • Is Elmer the adequate tool for my projects? In this document you find a short introduction to what Elmer can do and the main executables.

  • How do I start learning Elmer? Simply put, Elmer does not require basic users to master all the fundamentals of FEM, so following the getting started guide seems a good starting point. There you learn how to install, configure, and run the software.

  • Where do I get the binaries of Elmer? If willing to run in Windows, the previous link provides the compiled binaries; there are also instructions for installing directly in Ubuntu as well as all the documentation and other test and sample cases.

  • I feel alone, where do I find other users? The forum seems to be moderately active, so you can go there to chat with other users and developers if you are not in a hurry.

23.2 Limitations and issues

  • Currently the GUI is not able to import SIF files generated manually because it stores its state in a XML file; to be able to re-run cases from the GUI users need to create the equivalent case (eventually using the free text fields) in the GUI itself before regenerating a SIF file. Notice that this will overwrite the SIF file, so keep in mind to backup the file in another directory; that is especially required for highly customized cases.

  • When exporting meshes from gmsh, consider using the extension .msh and not .msh2 as is often seen as a reminder of format 2 mesh; Elmer GUI is unable to render the mesh in this case. Notice that this has apparently no effect if running from command line.

23.3 Ongoing work

23.4 Retrieving materials

Because there are plenty of interesting materials in Elmer public directory, it is worth downloading it all and selecting what to keep later. In a Linux terminal one could run the following command. If you also want to retrieve the animations, binaries, and virtual machines, consider removing and/or modifying the -X options.

#!/usr/bin/env bash

URL="https://www.nic.funet.fi/pub/sci/physics/elmer/"

wget -r -l 20 --no-parent           \
    -X /pub/sci/physics/elmer/anim/ \
    -X /pub/sci/physics/elmer/bin/  \
    -R "index.html*"                \
    ${URL}