Advice needed for meshing for wall functions
 

Hello all

firstly, I read that y plus should be between 30 and 500, but nearer 30.

If the first cell height is such that y+ = 30, how fine should the mesh be immediately afterwards? My first instinct was to gradually increase frm the first cell height, but then I thought maybe it needs to be finer because the gradients are probably still quite high in that region. I just wanted to check...

I also have another question... how fine does the mesh need to be along the line of the surface. I'm dealing with 2d external flow with re of the order 10^4.
does somewhere around 1x10^-3 to 5x10^-3 sound reasonable?

Thanking you all

Dan