CFD Online Discussion Forums - Issue Importing NASTRAN file to STAR CCM+

Hi guys,

I am currently at university working on a CFD project and am teaching myself how to use CFD packages.

I began with ANSYS Fluent and now need to change to STAR CCM+ for simulation/solving. However, I wanted to use my mesh file from ANSYS as I don't want to spend time redoing work I've already accomplished and going back to square 1. So, I've exported my mesh file as .nas and loaded it into STAR...

So, my issue- my model is an electric motor where I am investigating the air flow, so the free space between rotor and stator. In ANSYS I've defined the "free space" as a fluid so it differentiates it from the solids. However, when importing into STAR it's treating the domain, rotor, stator & free space as one part/ a single geometry in the geometry tree, so I am unable to select the fluid region to provide any information and define the rotor/stator as solids. I am (possibly incorrectly) assuming this is due to the type of format of a .nas file, however it's the only format I can export from ANSYS and import into STAR.

I have no knowledge of STAR and I have so far only learnt how to split by patch however this option is grey-ed out. I will continue messing around with it myself, but am hoping someone knows if there's a quick way to get around this solution (export as different file type?) as otherwise I'm going to have to go back to step one and repeat all the work I've done so far in ANSYS, which for obvious reasons I'd rather not have to do.

I've tried searching for this issue but mostly it's just people having importing issues rather than issues with the model once imported or else going the other way of importing a STAR mesh to Fluent.

Thanks in advance :)