SimScale CAE Forum

Disappearing Topological Entity Sets after Creating Enclosure During CFD

Hey, I’m using the tutorials to learn more about CFD solutions for airflow. I was following this one verbatim:

Here is my project as I followed that tutorial;
https://www.simscale.com/workbench/?pid=5610761644394947419&mi=spec%3A11b34846-ea89-4780-bdf3-57abf8e391d3%2Cservice%3ASIMULATION%2Cstrategy%3A108&ps=analysis%2FCompressible--oneOf%2FboundaryConditions%2F4

You’ll see I am following it step by step, and created topological entities from the ball solid before generating the enclosure geometry:

Once the enclosure is generated however, my topological entities disappear:

Without the topological entity of the ball’s surfaces I can’t finish the final boundary conditions for rotation. I first noticed this for another project I was doing for a wing section, where I couldn’t include the no-slip wall of the foil surfaces. That’s why I imported this tutorial to figure out what I was doing wrong. However I have the same issue when following this tutorial.

S0, I copied the SOLVED tutorial for the golfball ;

https://www.simscale.com/workbench/?pid=8082287462749046553&mi=spec%3Af2b57f60-8c47-4db6-9f63-ad33698bb0a6%2Cservice%3ASIMULATION%2Cstrategy%3A67

And the topological entities are there. But, when I delete the enclosure results and re-run the geometry operation, they disappear for me. I can’t seem to create the geometry enclosure and preserve topological entity sets that I pre-defined. Can you help point out what I am doing wrong?

Hi @FreeStroke,

I previously had this issue as well. While I dont have a full solution, a workaround I do is to do area selection. Simply hide all the bounding walls and use the selection box to select all the faces.

image

Try that out, that will help save you some time unless someone figures out a way to preserve the assignments.

Thanks for the suggestion; that’s how I selected the faces on the original model of the ball. Once the enclosure geometry is generated however, the model of the ball is removed as well as those topological entities, so only the created fluid enclosure remains. So the “faces” seen in the model are now the negatives, and belong to the fluid. Of course, there is a toggle option in the geometry enclosure dialogue box to “Keep existing parts”, but then the CFD analysis will have a volume of fluid AND the existing part to mesh and solve for. According to the tutorial, the only way to maintain reference to the surfaces of the original part (ie golfball) is to pre-define these topological entity sets before generating the enclosed volume of fluid. That’s where I am stuck.

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