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Cross-section of the boundary layer between two mesh zones

Antoinemmm

Hello everyone, I am using HyperMesh CFD for the first time and I have encountered the issue shown in the attached picture. My boundary layer, generated by the 'Edge Layer' tool, gets cut off when it intersects with the edge of a mesh refinement box. I am looking for help to ensure my boundary layer remains continuous. Thank you in advance

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acupro

If you can attach the .hmcfd database we can help to diagnose the issue. Please attach it to this post. Also - which version of HyperMesh CFD are you using?

Antoinemmm

Hi, I apologize, but I cannot share my original files due to confidentiality restrictions. I am currently using Altair Hypermesh CFD 2025.1.0.28.

As my company has a partnership with Altair, could you please let me know if I can contact a dedicated support engineer to resolve this issue? Alternatively, I can provide a .hmcfd database that reproduces the error using a dummy geometry.

Best regards,

acupro

You are welcome to submit a support ticket for somebody on the team to assist. You could also attach a sample/dummy database. Either way.

Antoinemmm

dummy_geo.zip

I have attached a dummy database reproducing the issue. I hope this helps you find a solution. Thank you.

acupro

The adjacent edges appear to have the same Edge BL definitions, but are in different Edge BL sets. Here they are all in the same Edge BL set.

It might also help if you make the surface edges come normal to the edges with the BL rather than at an angle.

Antoinemmm

Assigning both to the same Edge BL set creates a conflict due to the mesh density mismatch between the two surfaces.

I want to keep different average element size for both surfaces of mesh

acupro

Agreed - that would be the problem - no good way to reconnect such drastically different mesh sizes. I would guess the meshing could handle a small difference - but nothing that large. You may need to experiment to see what kind of size change it could handle, if any, then maybe break up the surfaces/edges into several sections to go little by little eventually to reach the desired sizes.

acupro

Are you exporting from HyperMesh - or from HyperMesh CFD?

Maybe try .msh file instead of .cas file?

Do you intend to run a 2D / Planar simulation in Fluent? SimLab might be better suited - but I'm checking with others to see if HMCFD has a reliable workflow for that.