Mesh import - gambit

Using SimScale CAD & Meshing
1

Hi all,

I was interested in using a mesh I have created using gambit. nothing complex, just the flow around a cylinder.
Is there a way to import directly this mesh into simscale?

From what I have seen it seems that it cannot be read automatically, therefore, which is the strategy you suggest to me to accomplish this operation?
Should I switch to OpenFOAM, convert it and then upload it, or there is something more automatic?

Thanks a lot for any help you can provide me:)

2

@Fabio88,

unfortunately we do not yet support a native import of Gambit meshes. Therefore you would need to get your mesh first in one of the upload formats SimScale does support right now. It seems like you’re interested in CFD anyways - so the OpenFOAM format might be the best way. Can you convert your mesh into the OpenFOAM format? Then simply zip the “constant” folder and upload it (find more info on this in the documentation: Meshing in SimScale | Simulation Setup | SimScale)

Let me know how it goes and if you need further help. We are working on providing support for more format options when uploading a mesh. So this upfront conversion should not be necessary in the future anymore.

Out of curiosity: What’s the main reason that you’re meshing locally?

Happy Simulating!

David

3

Hello David,

thanks a lot for the information.
I was thinking I should do the conversion and indeed you confirmed it.

The main reason I am meshing locally is that I would like to check the results I am obtaining in Fluent with the ones I can achieve in OpenFOAM, therefore I would like to have a cross-check without any influence of different meshes.

Cylinder seems to be an humble object but in reality simulations have quite many issues:)

Have a nice day and thanks again for the help.

Fabio

4

Fabio,

excellent - would be interested in the results you’re getting. And agreed on the cylinder! I worked a lot with multiphase flows and it’s interesting how many hours of scientific work did go into the simulation of a single droplet hitting the ground :smile:!

Regarding validation - I can recommend this page of the documentation: Validation Cases | Cloud-Based CAE Simulation | SimScale, where some of the validation simulations that were done on SimScale are published. Depending on if you’re looking into flow THROUGH or AROUND the cylinder, these might be of particular interest:

FlowOverCylinder-results-Vcross-section.png1412Ă—932 1.23 MB

TurbulentPipeFlow-geometry.jpg1316Ă—653 64.4 KB

Best,

David

2 Likes
5

Hi David,

thanks a lot for all the info!
I am actually studying the external aerodynamic for a cylinder at the same Re of the one you posted:)

I managed to import the mesh.
Actual operation are:

  • Create a folder with the OpenFOAM structure called cylinder (I actually took one OF tutorial, copy paste the folder, deleted the content of polymesh (I do not know if the last operation is really needed))
  • Copied my mesh inside the main folder (but you can call this mesh from everywhere, just I think is nicer to have in the correct folder)
  • Gambit: the mesh exported from gambit is the same one you can use for fluent. Avoid the use of periodic boundary conditions since it cannot be converted later. Make for example symmetry boundary conditions and you can change them later on into simscale
  • I used the command fluent3DMeshToFoam. it should be called from the main folder (Cylinder in my case) and include the name of the mesh (e.g. fluent3DMeshToFoam cylinder.msh). Then take your file constant, zip it and upload it into simscale.

It seems working.

For the staff: it seems to be that it is not possible to change the names of the various components I created. I guess this can be done only in the geometry section. Not a big deal, but maybe an idea for you:)

Fabio

6

Fabio @Fabio88,

excellent - glad it worked! In the future, the conversion to an OpenFOAM mesh format should not be necessary anymore.

By “components” do you mean the faces/patches of the mesh you uploaded? Indeed, this is something we are right now working on. Or did I understand your comment wrong?

Now happy simulating with the mesh!

David

7

Yes I was meaning those.

Soon I will start simulating.

Need a little bit time to check all the settings :slight_smile:

Have a nice weekend!