How to create zero thickness internal walls in a given mesh in OpenFOAM?
 

I know using topoSet and subsetMesh along the lines of the mesh/moveDynamicMesh/simpleHarmonicMotion tutorial, one can cut holes into a mesh and obtain new patches. How can something similar be achieved with a vanishing hole, i.e. can a set of internal faces be turned into two touching patches with opposite orientation?

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also posted at http://scicomp.stackexchange.com/q/2715/1669

As gschaider posted at SE, I simply need to use the createBaffles tools