I've a question regarding the definition of the velocity boundary layer. The boundary layer is defined (correct if I'm wrong) as the region close to the body where viscous effects are important and cause gradient of velocity from 0 (non-slip) at the surface to the free stream. Moreover it can be divided in several zones according to the Reynolds number (ratio of inertia to viscous forces).
Now my question: why the turbulent boundary layer it is still called "boundary layer" even though, at high Re, the effects of inertia forces became predominant? I know that there is still a laminar sub-layer to full fill the non-slip condition as well as that in the turbulent boundary layer there are significant gradient of velocity.
I hope the question is clear