[Clau.77]

Hello!


As you can see in the attachted foto, i have a tray filled with chocolate bars, that I want to mesh with snappyHexMesh and then use chtMultiRegionFoam. So in the end I want to have three regions: the tray, the chocolate and the air. The problem is, that the chocolate bars are not connected, so I don't know how to get them to be in one region.

I tried putting all the chocolate bars into one stl file but I understand know that snappyHexMesh can't deal with that.



So should I put all the bars in seperate stl files? How can I combine them into one Region then? Or is there a smarter way to do that?


I have been struggeling with this for over a week, I would really appreciate your help!

[Yann]

Hi Claudia,



What OpenFOAM version are you using and what is your current workflow to mesh this case?


Yann

[Clau.77]

Hey,


I am using version 8. I created the geometry in inventor and exported the geometries as one step file to Salome. There I created a partition and exploded the partition again. After that I exported the stl files (tray.stl, chocolate.stl,...) to OF. Then:
- blockMesh
- surfaceFeatures
- snappyHexMesh
- splitMeshRegions

[Yann]

I did not try this in OpenFOAM-8, however I think it's worth trying:

• Define a cellZone for each region you need in your case in snappyHexMeshDict (tray, chocolate and air)
• Use splitMeshRegion with the -cellZonesOnly option

The trick lies in the splitMeshRegion option. As long as every chocolate bars belongs to the same cellZone, it should end up in the same region.

Let us know if it works for you.
Yann

[Clau.77]

Thank you Yann!


Do I need to use topoSet to create the cellZones or is there a way to do it wothout topoSet?

[Yann]

You can either use topoSet, or define it directly in snappyHexMeshDict in the refinementSurface section:

refinementSurfaces
{
    sphere
    {
        level (2 2);
        
        cellZone sphere;
        cellZoneInside inside;  // outside/insidePoint
    }
}

You can check some chtMultiRegionFoam tutorials such as "heatedDuct" to have a functional case using a similar syntax.

Hope this helps,
Yann

[Clau.77]

I finally did it! My problem was that i tried to define the air as cellZone in snappyHexMesh too, but its easier to define the air in the blockMesh and the rest in snappyHexMesh.


Thank you for your help!