SnappyHexMesh: How to cut a nozzle out of a solid block, and mesh both
 

Greetings

embarrassing enough to have to ask again, but I don't get really ahead with this only looking at prepared cases.

Consider a simple block of some solid (the boundary shape will be quite similar to the cube I use as blockMesh background mesh for snappy hex), where some flow channel is cut out. The flow channel is aligned with some principal axis of the cube and has one inlet and one outlet (say on minX and maxX).

The geometry is present as a single .stl file with, unfortunately, no patch names included.
It was possible to mesh this with snappyHexMesh as a proof of concept, but due to the setting only the solid part was meshed and not the flow channel, I think due to the location in mesh parameter. In the end it is necessary to have both the solid and the inner fluid or nozzle region meshed, to do some conjugate heat transfer simulation
(which is proper set up for some third party tool and shall not bother me at the moment)

The fluid and solid regions shall have "clean" neighbouring cells with shared faces. I think the most apt tutorials for this are the snappyMultiRegionHeater in multi- region foam, or even closer the snappyMultiRegion tutorial of Tobi Holzmann, but there the geometry is assembled from multiple named .stl files, and not one that must somehow be divided. Maybe I just have to define the inlet and outlet batch in the .stl and snappyHexMesh dict, do 2 or 3 other things and I will be there ;-)

Some hints to attack this in a clever way are greatly appreciated, I should be able to do the work then using that tutorials

All the best,
Marcus