Computational Fluid Dynamics (CFD) workbench using OpenFOAM

A subforum specific to the development of the OpenFoam-based workbenches ( Cfd https://github.com/qingfengxia/Cfd and CfdOF https://github.com/jaheyns/CfdOF )

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Re: Computational Fluid Dynamics (CFD) workbench using OpenFOAM

Post by oliveroxtoby »

Crossleyuk wrote: Sun May 22, 2022 11:41 am Hello All,

Moved back to my old Forum page to keep my new VXA page tidy. I have a request for a little help on the next step of my CFD equiries on a new CFD model. This is the failure I received and the report text.

Hope you can help, realy keen to make progress
Looks like the solution diverges in a few iterations. Very difficult to tell anything from the output. If you can share your case that may help. Alternatively, setting the write interval to output every iteration may give you some clue as to where things are going haywire.
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Re: Computational Fluid Dynamics (CFD) workbench using OpenFOAM

Post by Crossleyuk »

Thanks yet again Oliver. This is another first for me but thak goodness for your support. I'll follow your suggestion and take a closer look. Cheers :geek:
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Re: Computational Fluid Dynamics (CFD) workbench using OpenFOAM

Post by Crossleyuk »

Sorry Oliver, I can't find how to allow me to sett the "write interval to output every iteration". I expected to see it in the cfdof parameters. Where can I change that?
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Re: Computational Fluid Dynamics (CFD) workbench using OpenFOAM

Post by Crossleyuk »

Here is the case that I'm working on. It's a little complicated because I've included the external an internal components to the actual CFD flow regions. Hope it helps.
Body_Cyl_Axial_Complete_Rev_P2.FCStd
(431.45 KiB) Downloaded 11 times

Regards

Michael
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Re: Computational Fluid Dynamics (CFD) workbench using OpenFOAM

Post by trijonb »

Hi Michael,

Check your mesh, this is what it looks like currently (from your provided case).
mesh.png
mesh.png (210.91 KiB) Viewed 440 times
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Re: Computational Fluid Dynamics (CFD) workbench using OpenFOAM

Post by thschrader »

Crossleyuk wrote: Mon May 23, 2022 8:47 am Sorry Oliver, I can't find how to allow me to sett the "write interval to output every iteration". I expected to see it in the cfdof parameters. Where can I change that?
You can adjust the parameter in the solver data-tab.
alternative: edit control-dict after case writing.
write_intervall.JPG
write_intervall.JPG (60.03 KiB) Viewed 422 times
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Re: Computational Fluid Dynamics (CFD) workbench using OpenFOAM

Post by Crossleyuk »

Thanks, but very strange, this is the mesh from my case here. Exactly what I expected and have had in the past.
Body_Cyl_Axial_Complete_Rev_P2_Mesh.png
Body_Cyl_Axial_Complete_Rev_P2_Mesh.png (196.86 KiB) Viewed 396 times

So still confused ;) but as suggested, I'll now check the write interval.

Michael
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Re: Computational Fluid Dynamics (CFD) workbench using OpenFOAM

Post by thschrader »

This is what I get.
CheckMesh gives back a failed warning, see report view.
I dont know if this is critical for your simulation.
Have a closer look at the cylinders. It looks like that
there are some mesh inconsistencies...
I tried cfmesh ==> openFoam crash
snappyhexmesh: 30 min runtime, I gave up...
GMSH seems the best way, maybe there are some glitches in your model?
gmsh.JPG
gmsh.JPG (439.09 KiB) Viewed 376 times
gmsh2.JPG
gmsh2.JPG (198.49 KiB) Viewed 376 times
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Re: Computational Fluid Dynamics (CFD) workbench using OpenFOAM

Post by Crossleyuk »

WOW, thank you. Yet again I'm gratefull for your support and to be honest lessons. I now know what to be looking for now and in the future. I had the same problem with cfmesh so used gmesh. Great help and a clear direction for tomorrow, I'll remake that region of the model and mesh and check the details you've picked up. Fanatic help, thank you very much!

Michael
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Re: Computational Fluid Dynamics (CFD) workbench using OpenFOAM

Post by Crossleyuk »

HaHa,
I got exactly the same response as you for cfMesh abd gmsh gave me the one that you saw the concerns for. So I was away for a away for a while and thought I'd try SnappyHex. And this is what it gave me after 55 minutes 8-) .
Body_Cyl_Axial_Complete_Rev_P2_Snappy_Hex_Mesh.png
Body_Cyl_Axial_Complete_Rev_P2_Snappy_Hex_Mesh.png (162.37 KiB) Viewed 274 times
Image

So I'm going to rebuild that area of my case model and try meshing again. Thanks again, I learn so much every time we have these exchanges.

Regards

Michael
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