Big simulations where a good yPlus and reliable heat flows are needed in small areas
 

Hi, this Post was quite long, so I decided to shorten it.
My need was to get some information about the distribution of temperature inside a big warehouse containing a furnace and a cooling system equipped with powerful fans.
For this reason, I needed a good mesh in some small area of the warehouse, and a raw mesh elsewhere, in order to have an affordable model.
I thought that functions like “Multiple blocks –Face merging” in block Mesh, “stitchMesh” or “cyclicAMI” used in block Mesh were the best way to prepare a blockMesh mesh divided in 27 blocks (a 3D matrix 3x3x3), one with a nice mesh, and the other 26 blocks with a raw mesh, in order to use snappyHexMesh to shape nicely the interest region, but during some weeks of attempts I only got errors.
For these reasons it seems that the mentioned functions are not intended to easily prepare a structured block Mesh to have an easy job in snappyHexMesh, isn’t it?
So, what is the main aim of “Multiple blocks –Face merging” and “stitchMesh”?
Thank you very much for the information in any case, even if you consider my questions too simple to deserve an answer. :)
Best regards
Giovanni de Nobile