I am happy with the choice of boundary conditions for the field variables when it comes to resolving the boundary layer at wall patches.
My question is how strict is the y+ condition? Should the mesh be fine enough to ensure a y+ < 1, or is it acceptable to have a y+ < 5?
In addition, should the y+ condition be satisfied by all cells? Or is it enough to have the patch average below 1 or 5? I have extracted this data using the yPlus post-processing function.
This is with respect to an ABL flow around a building.