Learning Forum

[Johanna Hjeltström]

Hello! I am doing a fluid simulation where I first did a mesh in Flent Meshing. I have a problem with that cells disappear when I switch to solution though. Is it a mesh problem? Or something else?

There pictures is from Fluent where I am showing the mesh in a plane.

Best regards,

Johanna

[Federico]

Hello Johanna, 

there might be an issue with your mesh. Before you bring it to Fluent Solution, can you check the Surface and Volume mesh qualities? Also, I recommend performing a mesh check.

[Johanna Hjeltström]

Fluent meshing is not allowing me to perform a surface mesh quality check. The volume mesh quality is quite good in my eyes though, average orthogonality: 0.95, average skewness: 0.047 and average aspect ratio is 3.2.

I attach a picture of the mesh check because I don´t really know what it tells me.

 

[Federico]

The Mesh Check does not report any error, so this is a good sign.

In Fluent Meshing, clicking on the Surface Mesh task in your Outline view, you should then be able to Check Surface Mesh quality.

Please report the Maximum Skewness and Minimum Orthogonal quality, as these are better indicators than averages.

[Johanna Hjeltström]

The maximun skewness is 0.8 and the minimum orthogonality is 0.19.

I can not see the Surface Mesh task.

It just looks like this,

[Federico]

Hello Johanna, 

I'm sorry I assumed that you were using one of our guided workflows, such as the Watertight Geometry workflow. If not, then please provide details on the steps that you took to generate your mesh.

[Federico]

Have you given this a try?

Here are some workshops from our Ansys Innovation Courses library on the Watertight Geometry Workflow:
Tutorial on Watertight Geometry Workflow | Ansys Courses

[Johanna Hjeltström]

Oh, this is what I am using.

[Johanna Hjeltström]

Hello! 
Can you tell me more of what could be wrong with my mesh? I still get the holes in it despite me redoing it.

[Federico]

Ok, so you are using the Watertight Geometry workflow.

It is difficult to understand what those "holes" are from looking at your pictures above alone. What are you showing in those figures? How does that area look in your geometry/CAD?

[Johanna Hjeltström]

I can not show the whole geometry but it is basically just blocks stacked on top of eachother. 

[Johanna Hjeltström]

The holes never appear at the interference of the blocks. They always appear in the bulk volume. When I read the mesh I get the messages like "Skipping thread 82011 of domain 1 (not referenced by grid)", does that have anything to do with it?

[Federico]

Also, I don't think this is causing this issue, but we recommend using Share Topology at the CAD level, rather than doing this in Fluent Meshing. Share Topology is more robust in SpaceClaim or Discovery.

[Johanna Hjeltström]

I see! But will that make a change? Share Topology is used in the connection of the blocks, right? The holes that appares is not near the joints.

[Johanna Hjeltström]

Is this question for me?