[Aarib]

I am trying to simulate propeller in OpenFoam using the SHM. The meshing runs file if I use the default files from the propeller tutorial however the mesh is too coarse for my simulation. But if I try to increase the cells in blockMesh then the SHM does not snap the mesh to propeller and just give me blockMesh with inlet and outlet.

But if I use less cells in blockMesh then SHM works fine and snaps the mesh to the propeller. I don't understand why its doing this.

The same thing happens when I try to increase refinement level and maximum number of cells in SHM. Everything else remains the same. Can someone tell me why this happens?

[AtoHM]

I have not done this tutorial, but if the number of cells/levels (higher spatial resolution) is really the only parameter that is changing, there might be an issue with the STL file itself. If the input stl is not closed and your cell size is able to resolve the gap, snappy will stop working and just hand you back your blockMesh which is what you described.
You can navigate to your folder and run

surfaceCheck propeller.stl

to see if it is closed.