[enrin]

Hello everyone!

I'm here to ask a question concerning the meshing process.
My problem is that I have an .stl file that should be placed into a moving (overset) mesh and I would like to shape the moving external mesh as the .stl file itself. Then, since my case makes use of the overset mesh, I need to create an hole region in correspondence of the inner .stl.

So my idea was the following one:

1) Scale the internal .stl to get a bigger object of the very same shape;
2) Create an external blockMesh bigger than the .stl of the point 1);
3) Apply the snappyHexMesh tool (indicating as locationInMesh a point that belongs to the bigger .stl) to obtain an .stl shaped mesh
4) Create a dummy boundary patch of type "wall" on the snappyHexMesh
5) Assign this dummy patch to the original (NOT SCALED) .stl file in order to have a wall region inside the mesh

Actually, I don't know how to succeed in the point 4) because I do not know how to add this dummy boundary patch to the snappyHexMesh. I reckon that the createPatch utility is not working properly, since I do not have to create a specific path related to any features of the object. Maybe I'm wrong and there is the possibility to use the createPatch and succeed, even for a dummy boundary. I do not know

Please let me know if it is possible to do what I have planned or if there is another (smarter) way to do it.

I am fully available for further clarifications!

Many thanks,
Enrin

[Yann]

Hello Erin,

I am not sure to understand what you are trying to do, but the general workflow would be to create 2 cases: one for your background mesh and one for your moving mesh. Once both are meshed you can use mergeMeshes to merge them together and go on with the overset setup.

Regarding your moving mesh, you can use both your inner and outer STL at once in snappyHexMeshDict. As long as you define a point between these STL as your locationInMesh, snappy will only keep the mesh located between these 2 STL.

Hope this helps,
Yann

[enrin]

Thank you Yann.
I'm really sorry for the dumb question and stealing your time. I was already doing what you suggested in the second half of your answer but I had created a wrong .stl file so, the whole process didn't work.
Anyway, after reading your thread, I fixed it.