Meshing
The first step in setting up a case is to have a mesh of the geometry to correctly
constrain the simulation and detail the locations at which boundary conditions will
later be applied. Simple meshes can be created using the genbox tool, but the
most general and flexible approach is to use commercial meshing software such as
Cubit or Gmsh. NekRS requires the subsequent mesh to be in the .re2 binary
format which can be generated (through conversions scripts) from common mesh formats
such as CGNS (CFD General Notation System), EXO (Exodus II) or GMSH.
The genbox, cgns2nek, exo2nek and gmsh2nek tools are installed
by following the instructions in the Building the Nek5000 Tool Scripts section. We recommend looking
at the The README’s for the cgns2nek,
exo2nek or
gmsh2nek tools
if using them, with further information also available in the
Nek5000 documentation.
Mesh with Cubit
TODO Example of creating Exodus Mesh
Meshing with Gmsh
TODO Example of creating a Gmsh mesh
All your mesh should be hexahedral elements. Before exporting from Gmsh, you will need to set the mesh order to 2. The Gmsh mesh format must also be version 2, ASCII/binary format. If your Gmsh version shows a pop-up box when exporting the mesh, do not click “Save all elements” or “Save parametric elements”.
Creating a mesh with ?????? - CGNS
TODO Example of creating a cgns mesh