I have some Questions concerning Meshing.

As I know, the Subdivisions of the Near-Wall Region can be divided into 4 as follows, namely: viscous sublayer, buffer layer or blending region, fully turbulent region or loglaw region, outer layer.

Suppose I am using LES and NearWall Model Approach, I have to set the 1st grid point near the wall around y+=5. but what's then?

what's the stretching ratio of mesh normal to the wall and parallel with the wall (including along the flow and perpendicular to the flow)?

is there a constraint of the stretching ratio to keep it not larger than a certain number or what?

how many grid points do I need to mesh in buffer layer or blending region? and how many in fully turbulent region or loglaw region? outer layer?

Any help would be greatly appreciated.

Daniel

Could anyone help me on this topic? Thanks