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Problem Meshing Boundary Layer

Valued Contributor
Valued Contributor

Hey Everyone,

 

I need your help with a pretty simple Problem. I have to do a Benchmarking of the K-Epsilon Turbulence Model of a Backward Facing Step. So the geometry is very easy. However, I'm not able to set up the Boundary Layers.

When I use the Boundary Layer option from Mesh Control it seems to work fine but after updating the Mesh it does not show the boundary meshing. I'm asking myself if it is only a visual problem (elements are to small to be shown) or if in the end it is not meshing the boundary layer as it should.

On the other side, I tried to mesh the boundary layers with the "biasing on edge" function. I was wondering if there is a way to flip the direction in which the biasing is applied.

 

Thank you very much for your help

 

 

Regards,

 

Eiko

3 REPLIES

Re: Problem Meshing Boundary Layer

Siemens Legend Siemens Legend
Siemens Legend

Hi Eiko,

 

The Boundary Layer Meshing is applied via Mesh Controls on faces of your body to be meshed. If you do not delete or modify these faces (e.g. by deleting or splitting), the Boundary Layer meshing should be updated when you update the mesh after a polygon body change.

After meshing you will see different meshes in your mesh collector. Instead of only having a "3D_mesh(1)", you should have a "3D_BL_HexWedges(1)" and a "3D_Pyramid_Transition(1)" mesh in your collector. Switching them on and off, you can easily check how your mesh was built.

 

You can also use the Biasing on edge function to generate a similar effect of having smaller elements at the boundary layer. In the Biasing on Edge Command, you have a menu for "Bias Origin". You can select "Start of Edge", "End of Edge" and "Center of Edge" to control the biasing direction of your mesh control.

 

I hope this helps setting up the correct meshing for your body.

 

Regards

Boris

Re: Problem Meshing Boundary Layer

Valued Contributor
Valued Contributor

Hey Boris,

 

thank you very much for your support. However, it's still not working. I have a global Hex-Mesh so there will not be Transition elements. Maybe it's because the Boundary Layer Mesh Control only works on Tet-Elements? Not sure about that. Any reply will be much appreciated!

 

Attached you can see a screenshot. All meshes are updated and boundary layer is applied as you can see (blue Boundary Layer Icon on the Surface). However, it is not shown.

 

Best regards

 

Eiko

Re: Problem Meshing Boundary Layer

Siemens Legend Siemens Legend
Siemens Legend

Hi Eiko,

 

The Boundary Layer Meshing is embedded to the Tet Mesh Command. The Boundary Layer is generated with Wedges or Hexas (if you have a quad seed mesh on the surface) and then filled with Tetra Elements during the execution of the Tet Mesh command.
If you need a pure Hex Mesh, the Biasing mesh control could be used for that purpose.

 

Best regards
Boris