first of all thank you for your kind words! We try our best
Regarding the Mesh I first wanted to get rid of the “glitch” you were talking about. You could try adding this Background Mesh Box 1 - 1 Refinement again and see what it does. CFD is an iterative process anyway so expecting to have the right settings at the beginning is quite optimistic, well at least in my opinion…
Your question about the Y+ value is very valid and it has only been discussed once by our PowerUser @Maciek in this Post where he looks at the ISOsurfaces trying to make statements about the choice of Y+.
I am not an expert and would like to invite our PowerUsers @dylan, @1318980 and @Maciek to this discussion. But as far as I know in order to get an accurate simulation the first cell center must be inside the viscous layer we are looking at. Usually we consider Y+ to be smaller than 4.
BUT the size of your first cell must correspond to your turbulence model. For example k-omega SST requires a Y+ smaller than 1 whereas k-epsilon requires a Y+ of 30 - 60. I do not have values for LES though but we have to distinguish between fluctuations generated by shear at the wall & those generated by flow shear. I read on some pages that a Y+ of 1 is required. This would allow your LES model to capture the transition from the viscous layer to the developed layer with the appropriate turbulent energy transfer.
You can use the approach of @Maciek in order to get your Y+ (so during Post-Processing).
There are several tools out there that may help you esimating your Y+ , for instance:
I hope I could help you a bit with that. Looking forward to hear what our PowerUsers have to say to that and hopefully correct me if I made a mistake