[mmoelle1]

I am using the ANSYS CFD mesh import/export API to generate binary ANSYS mesh files, perform simulations with CFX and read the data from the result files back into our applications to process them further.

Is it possible to store "hidden" information in the CFX mesh file? These "hidden" information would be some meta information telling our application how the mesh file was generated, e.g., a mathematical expression describing how mesh points have been distributed. Meta information could be stored either as text or in binary format.

The very same question applies to the ICEM ASCII format. Is it possible to store extra information, e.g., in form of additional comments there?

Any help is appreciated.

Matthias

[ghorrocks]

If you are writing your own mesh input/output then can't you write whatever you like in the files?

Some alternative ideas: If the information is small you can put it in the file name. Alternately you can write a second metadata file with the same file name as the mesh file (but a different extension) but contains the metadata. Then the metadata file is clearly linked to the mesh file.

[mmoelle1]

Technically speaking, I can write this information to the file. The question is, under which category I should store it. It’s not vertices, elements, etcetera. Is there a category that is not directly interpreted as mesh entity?

[ghorrocks]

So aren't you writing your own format? So can't you define it to have anything you like in it, including a spot for metadata?

[mmoelle1]

Apologise for the confusion. In our in-house software, we use our own file format, where we can store all these meta information. Some part of the simulation should be done using ANSYS CFX. For that purpose, we export our mesh data into the binary CFX mesh format using the ANSYS mesh and result file import/export API. The resulting mesh file is imported into CFX5Pre, a case file is created and the CFX5Solver is called.

What I would like to do is to write the meta information (possibly as hidden "vertices", "elements", ...) into the CFX mesh file so that it gets "transported" along the simulation pipeline and is available once we read in the RES files back into our in-house codes.

[ghorrocks]

You can't do that. The CFX mesh file just contains the mesh and there is nothing in it which just gets passed through to the results file. Well, nothing that I am aware of anyway.

I would extract your metadata and put it in a separate file. Then in your post processing script you can read the meta data file. What sort of meta data are you intending to pass?

[mmoelle1]

A couple of integers (number of grid points in x,y,z direction of a structured grid) and strings of the form 'tan(x/2)' (I could convert them to binary data).

Thanks for your effort. I wanted to avoid separate files since users often combine the mesh file with the wrong meta information file (I have experienced that in the past).

[ghorrocks]

You can put the file name of the mesh file the metadata refers to in the metadata test file. Also you can have a file name convention which says the mesh file and metadata file have the same file name, only the extension is different. These approaches would minimise the two files getting mixed up.

I cannot see any other option than having a separate metadata file.