Topological Entity Error in Incompressible CFD Simulation (BCC Lattice)

Using SimScale Fluid Flow / CFD
1

Hi SimScale Team,

I am trying to perform an incompressible CFD simulation of water flow through a BCC lattice structure.

Project URL:
https://www.simscale.com/workbench/?pid=3754054932019217564&mi=spec:3cf238b3-39dc-4525-a524-6aeb0583462b%2Cservice:SIMULATION%2Cstrategy:1&ps=analysis%2FboundaryConditions%2F2

What I have done so far:

  • Uploaded my CAD model (BCC lattice inside a cuboid domain)

  • Assigned material as water

  • Followed the onboarding/tutorial steps for incompressible flow

  • Defined boundary conditions (inlet, outlet, walls)

Issue:
When I click on Start Simulation, I get multiple errors like:

  • Unknown Topological Entities: region1

  • Unknown Topological Entities: face2007, face2012, etc.

Observation:
It seems like the simulation is not recognizing some faces/regions that were previously assigned in boundary conditions.

Screenshot of error attached

What I need help with:

  • How to correctly assign/select internal fluid regions for lattice structures

  • How to fix these “unknown topological entities” errors

  • Whether I need to redefine boundary conditions after geometry/mesh changes

Any guidance would be really helpful. I suspect I might be selecting the wrong faces (outer vs internal lattice faces), but I’m not sure how to properly define the fluid domain for this case.

Thanks in advance!

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3

Hi,

There’s currently an unexpected behavior where a “Use mesh as domain” button is shown for incompressible simulations. If you see this message showing up after creating the geometry, just ignore it and proceed to running the simulation.

By clicking on it, you will lose your assignments and, after re-doing them, you will see these error messages that you posted.

So now just re-run the mesh, re-do the boundary condition/material assignments, and ignore the mesh warning if it shows up. We are expecting this unexpected behavior to be resolved soon.

Cheers