Wall Layers in Meshing

[knewsomeN8P59]

Hello all,

I have my model in CFD and I can use surface and edge sizing and all that. My question is how do I make wall layers on it? I have wall layers enabled. In a separate thread, it said they would be created automatically wherever a wall is, but my model is just the fluid volume through a pipe, no model of the pipe itself. I assigned the "walls" (not the inlet and outlet) as Slip/Symmetry BCs. Is it possible to create wall layers without the wall modeled?

Thanks in advance

[Radwan-Almsora]

Yes, you can absolutely create wall layers (known as inflation layers) without modeling the solid pipe itself. In Computational Fluid Dynamics (CFD), modeling just the fluid volume is the standard approach.

However, the reason your wall layers are not generating automatically is due to your boundary condition assignment: inflation layers will not grow on Slip or Symmetry boundaries.

[knewsomeN8P59]

What boundary condition should I use then? I don't see a simple "Wall" or "No slip" boundary condition like in ANSYS

[obulesub]

Hello @knewsomeN8P59,
 

We're following up to see if your issue has been resolved. If you still need assistance, please let us know and we'll be happy to help.
 

Thank you for being part of the Autodesk Community.

[morgann5238]

Interesting question. My understanding is that wall layers are typically generated on boundaries defined as walls. If the surfaces are assigned as Slip/Symmetry instead of Wall boundary conditions, the mesh may not create boundary layers there. Hopefully someone with CFD meshing experience can confirm the best approach.

[obulesub]

Hi @knewsomeN8P59, 

Good afternoon! Please let us know if you require any further assistance regarding this matter. If any of the provided comments helped resolve your request, kindly mark the relevant response as the accepted solution. Alternatively, if you found a solution through another method, we would appreciate it if you could share the details with us.
 

[CGBenner]

@chris_smith1 

Good morning!  Is this topic something that you might have some ideas on?  Is this a CFD question, or more of a Fusion modeling question?

[chris_smith1 · Accepted solution]

@knewsomeN8P59 

Hi there! @CGBenner Thanks for tagging me .

Wall layers are generated in CFD as a part of the meshing process.
They will be generated at the edge of any fluid material, regardless if they share a surface with a solid material.

When using the slip/sym BC they are not modeled as part of the fluid domain as the slip/sym bc assumes that there is fluid on the other side of the surface that is moving the same. Essentially, it allows free movement (frictionless) parallel to the surface, but doesn't allow penetration along the surface normal (perpendicular to the surface). If you're using that BC on the edge of the model, no wall layers should be generated, as they would not represent the user-defined conditions. 

There is no 'no slip' bc as that is the default behavior. 

Let me know if that answers your question or if there is additional explanation I can provide 🙂 

[knewsomeN8P59]

Thank you, I am just used to ANSYS where you have to define a "no slip" BC (or maybe you don't and I'm just being redundant on there lol). Thank you!