Learning Forum

[rachels1001]

Hey guys,

I am having an issue with creating a hex mesh for this geometry.

My problem is that I also have to include inflation layers at the walls of the central body. Hex dominant methods are not compatible with inflation, and when I've been trying to implement a multi-zone mesh, it tells me that the meshing is failing. I've enabled free mesh type in the multi-zone mesh.

I feel like I probably need to slice the central geometry to implement the multi-zone mesh, but I'm a little confused about how I should slice it and how to select the source faces?

I've gone over the multizone mesh pages on Ansys help, any help is appreciated!

Thanks,

Claire

[peteroznewman]

Hey Claire,

Never, ever use Hex dominant mesh methods on a CFD mesh.  It says so in the ANSYS Help system.

This method gives horrible elements in the center of the volume, which a Mechanical Solver does not care about but which ruins CFD solutions.

Yes, you should slice the geometry into six-sided bodies. These can then be meshed with Sweep method. With sweep method, you can bias the elements along the sweep to create "inflation" layers without using the Inflation mesh control.  Maybe you will be sweeping parallel to the flow, then two edges of the source face can have bias to create the "inflation" layers.

Regards,
Peter

[Manel40]

Hi Peter; 

 

I don't see why  Cvelikonja must slice his or here geometry to apply Sweep method ? What should happen if sweep method is applied without slicing 

geometry ? 

Thanks you very much for response

Best regards ,

Manel

 

 

[peteroznewman]

Hi Manel,

Sweep only works on six-faced bodies. If you apply a sweep method on a body with more that six faces, it will fail and the mesher will use the default method instead.

[Manel40]

Ok thanks you a lot

[Rob]

Just to add, we've had good success using an inflated poly mesh for cyclones. Make sure to pick the correct turbulence model too! 

[HannekeCrielaard]

Hi Peter,
Thanks a lot!
May I ask were you found this is the ANSYS help system? So i can refer to it?
Kind regards,
Hanneke.

[Rob]

Have a look in Mesh Methods in the Meshing User's Guide, you'll need to expand the Capabilities sub-menus.

[tumulpurwar]

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[tumulpurwar]

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[tumulpurwar]

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Hi peteroznewman

If i follow your advice of splitting fluid domain to get sweeping of mesh..everything go fine..but i get surfaces where i make split in fluid doamin, when i go to fluent, in boundary condition menu, these all surfaces come, and than there they want to be define with wall, or symmetry or inlet or outlet etc...how i do split in spaceclaim, so that i dont get theses surfaces?

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[tumulpurwar]

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[tumulpurwar]

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My extra generated boundary conditions due to split surfaces

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[peteroznewman]

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tumi

In SpaceClaim, on the Workbench tab, use the Share button. That prevents lots of walls in Fluent.

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[tumulpurwar]

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Hi thanks peter

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[tumulpurwar]

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