[Nek5000-users] Setting up a case from scratch

[nek5000-users at lists.mcs.anl.gov]

Note that this should be relatively trivial to do with the MOAB-based version of Nek (MOAB can read gmsh meshes 
already).  I'm not sure whether you can specify higher-order hexes in gmsh, but if you can, start by generating those 
(27-node hex).  Building and running Nek on MOAB is described in the Nek user's guide and on the nek wiki.  The 
examples/moab problem is a MOAB-based one, showing how to do this for a fluid-only problem; moab_conjht demonstrates it 
for a fluid/solid problem.  Note that the user documentation on text input is a bit out of date, so refer to the moab 
example rather than the user's guide for that (will take this as an indication I need to update the user's guide and wiki).

As for boundary conditions, I'm not sure how this is represented in the gmsh files (whether groups of nodes/faces are 
indicated in the file, or whether a field on nodes/faces/sides is used to indicate this).  If the former, these should 
read into MOAB sets marked with NEUMANN_SET or DIRICHLET_SET tags; if the latter, you'll have to interpret this data in 
the .usr file to set the boundary conditions.

MOAB's gmsh reader is not parallelized, so if you want to run this problem in parallel, you'll need to translate into 
MOAB's .h5m file format, then partition, as described in the wiki instructions.  Building MOAB builds also 'mbconvert', 
which converts between any file formats read/written by MOAB (for that matter, partitioning with MOAB's tool would allow 
you to read the gmsh file directly and output the partitioning info with the mesh to .h5m).

- tim


On 11/27/2012 03:04 AM, nek5000-users at lists.mcs.anl.gov wrote:
> Hello
> I want to setup a case of 2d cylinder in a channel. I plan to do this way
>
> 1. Make mesh in gmsh
> 2. Convert to vtx
> 3. Setup in prex and read vtx mesh.
> 3.1 make curved sides
> 3.2 set boundary conditions
>
> I have already tried all these steps partly. I want to know if there is any easier way to do it. Especially making
> curved sides and setting boundary conditions needs to be done per boundary edge. Is there a way to make it faster ?
>
> Thanks
> praveen
>
>
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              Tim Tautges            Argonne National Laboratory
          (tautges at mcs.anl.gov)      (telecommuting from UW-Madison)
  phone (gvoice): (608) 354-1459      1500 Engineering Dr.
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