Connect inflation layers around a corner between two split bodies

Hi, 

Thank you very much for your question. 

Unfortunately, it is a bit hard for me to understand the block topology in this case. In other words, I am not understanding where each block ends. Is there any chance you can post some additional images to understand this; or perhaps a very simple Fidelity Pointwise file showing this particular topology? 

In addition, it seems that you are using a regular extrusion to create the boundary layers. Have you tried using the T-Rex algorithm for this? 

Thanks much!

Hi,

of course. I am using a CAD model and create the blocks from its topology.

Here you can see the white part. This should be the block with inflation layers defined as a porous volume.

The other part above is a different block and both inflation layers should be connected.

The connected inlation layers should be around the edges like the red lines you can see here:

I haven't tried T-Rex for this yet, I only used the normal extrusion. Do you think this would work better?

Thanks for your help!

Hi, 

Thank you very much for the information. 

Yes, I would recommend using the T-Rex algorithm as it will allow you to create the grid that you are looking for in a fraction of the time. Furthermore, I would also recommend using the Automatic Surface Mesh (ASM) and Automatic Volume Mesh (AVM) tools to complete the grid in a fraction of the time. 

Please note the following:

• The first step when creating a grid is "preparing" the CAD data for meshing. This includes assembling everything into a single watertight solid model and assembling the quilts as needed to defined the desired meshing regions.
• Once the above is done, you can use ASM to quickly create the surface grid (domains).
• Once you have the surface grid, you can use AVM to create the volume grid (block).

If you are not familiar with the above workflow, I would recommend reviewing the following:

• Basic Concepts: https://youtu.be/7ynTrsuG80I?si=o1EiaEc-raqmO8Wg
• ASM: https://youtu.be/VmAYwRbChMk?si=7_cfopgR3sMwEI_O
• AVM: https://youtu.be/EU1Cb2KeK-U?si=UOangATVOOK4iZCw
• Also note that you have a wealth of material in the User Manual (Help, User Manual) that will guide you through the most efficient mesh generation process. 

I hope this helps. 

Hi,

Thank you for your help.

I am aware of the workflow you mentioned above. I only looked for a smooth way to connect both inflation layers.

I will try the T-rex algorithm.

Thank you very much.

Hi, 

Thank you very much for your quick reply. 

It is good to hear that you are familiar with the recommended workflow.

You will likely generate the smoothest (and faster) grid with the use of ASM to create the surface grid and AVM to create the two blocks. Inside AVM, you will be able to set up the T-Rex algorithm for each block with the corresponding boundary conditions.

Thank you very much for your time.

Hi, 

Thank you very much for your quick reply. 

It is good to hear that you are familiar with the recommended workflow.

You will likely generate the smoothest (and faster) grid with the use of ASM to create the surface grid and AVM to create the two blocks. Inside AVM, you will be able to set up the T-Rex algorithm for each block with the corresponding boundary conditions.

Thank you very much for your time.

Hi,

I tried T-Rex several times and got the following problem now:

As you can see, the inflation layers alsways end in the edges between the blocks. (The porous body is between the red lines, the other 2 bodies are fluid)

Is there a specific setting to connect it around the corner and also between blocks in general?

Thank you!

Hi, 

Thank you very much for the additional image. Now I better understand the topology you are working with. 

The T-Rex algorithm on the lower red interface domain stops because this domain hasn't been set to a Match T-Rex boundary condition. In addition, you need the Push Attributes turned on. 

As for the top red interface domain, T-Rex won't be able to make the 90 degree turn with the topology as-is. Even if you set the top red domain to a Match T-Rex BC, both BCs, the Wall and  the Match will be coplanar preventing the result you are looking for. 

One possible option in this case would be to change the topology slightly and move the red block down just enough to allow the T-Rex algorithm to make the desired turn (image below).

Please let me know if this would be a reasonable approach for you., 

Best regards.

Hi,

Yes I will try that.

But in this case, extruding in normal direction should also work, right?

Because it connects smoother than T-Rex cells.

Thank you!

Hi, 

You are very welcome. 

In my experience, T-Rex is usually what will allow for a nice transition in corner cases like this one. As far as I can tell, and considering I don't have the entire geometry, my last image looks pretty similar to your original image depicting your end goal. Based on this, T-Rex with the slight topology change would be my recommendation. 

That being said, you are welcome to give the normal extrusion a try but I suspect you may need to define additional topology in that corner in order to make the turn you are looking for. 

I hope this helps. 

Best regards. 

Hi,

 the normal extrusion worked pretty well around the corner:

After working with this, I got two more questions.

1. How is it possible to define conformal surface meshes between the two large areas to create a periodic boundary (next picture, 2 red arrows show the 2 domains of the boundary layer at the bottom and the surface mesh above)?

I only found out that I can go by rotating. But this would destroy the block with my boundary layer because the extrude also creates a separate block.

Is there a way to simply select the surfaces and set matching surface meshes as a boundary condition?

2. Do you know how to use hex dominant meshing for volume meshes? I only found the surface mesh option with hexes and tets. I am pretty sure there is also an option to use it in volume meshes somewhere.

Thanks for your help, I really appreciate it!