Boundary layer is necessary or not?
 

By the past articals, it said that the boundary layer in suction section is more important...

Is the boundary layer should be set in mesh file when I simulate in a complex profile?

What is the different in the results without using boundary layer?

sincerely~

it depends on what you want to compute.
if BL effects are to be investigate, then you may use BL for best approach.
You can compute your model with and without BL, you will see the difference, or not. Once again it depends on the your model.