create mesh from two blockMeshDict files
 

Hi I have these two blockMeshDict files, I want to create a single mesh from they. I tried to mergeMesh, and then run stitchMesh but the stitchMesh throw some errors, that I dont know how to solve, because the patch that I want to merge are identical gometrically speaking.

Or another option maybe cutting the inner mesh from the another but I dont know if its posible to do it