Currently I am working on the bubble dynamics with OpenFoam. I want to use a fixed-grid, sharp-interface method for it. Is it difficult to implement a cut-cell approach for moving boundary in OpenFoam? Please give me some suggestion, thanks very much.

Is there any class that I can deal with just one or two cells? For example, I want to cut a cell by a plane or merge two adjoining cells.

[lucchini]

Hi Chen,
you can cut cells and deal with moving boundary by means of the mesh modifiers implemented in OpenFoam.
Have a look at the $FOAM_SRC/topoFvMeshes, $FOAM_TUTORIALS/icoTopoFoam and $FOAM_APP/incompressible/icoTopoFoam

If you want only to move boundaries without changing the mesh topology you can have a look at how the mesh is moved in the movePiston.H file in the $FOAM_SRC/engine/include

You can also find something useful in the discussion group, have a look to the "Dynamic Mesh Changes" topic in the tree view.

bye
tommaso

[mattijs]

Hi Chen,

Cut cell by plane: the closest example is the mesh/advanced/refineWallLayer. Defines cut through cells by the cut through the edges and/or vertices.

Merge two adjoining cells: mesh/advanced/removeFaces

Thank you!
I have tried the class cellCuts and it seems to work.

[mattijs]

Would be quite interested to see some examples if you have something working.

I have generated a uniform 2-D mesh using blockMesh. Then I used the removeFaces to merge two adjoining cells by adding the adjoining face into the faceSet. But I got an error message "XXXX face is not internal". Can you tell me why?
Thank you very much for your kind reply!

[mattijs]

Are you sure the faces you're trying to remove are internal (i.e. inbetween two cells)? Use foamToVTK with the -faceSet option to display them.