subtract volume in blockMesh
 

I am wondering what is the best way to subtract volume from a block in blockMesh. I have attached a drawing of what I want to do. I have an 8 point block, but I want to remove another 8 point block from somewhere in the middle of it. Is there an easy way to do this, or do I need to create 4 separate blocks which surround the empty space and then merge the patches like i've drawn at the bottom of my attachment?

Greetings Adam,

If you have properly defined all of the cells, then you can use setSet to:

• select the cells to be removed (which means that they must already exist... ironic, I know);
• then invert the selection;
• then use subsetMesh to save only the last selection of cells.

How to use setSet:

• Good particle example, although not very advisable in some situations: http://openfoamwiki.net/index.php/SetSet
• When in doubt, like setSet states at the start, type the help command!

Best regards,
Bruno

Bruno,

This worked great, thanks! I ended up following the damBreakWithObstacle tutorial ($FOAM_TUTORIALS/multiphase/interDyMFoam/ras/damBreakWithObstacle), for anyone else who's interested.