A boundary layer going turbulent can cause a lot of low frequency noise and/or vibration, and even if not really audible, it can still make the pax uncomfortable, and possibly even sick.
Could some please stop confusing turbulent boundary layers with separated flow... a turb b.l. is not going to do that, heavily separated flow might cause buffeting & noise though
Turbulent boundary layers are much more resistant to separation than laminar ones.. some obviously know this, quite a few don't. That's why we stir up the flow in the boundary layer (with say voretx generators), to get an early transition to turb b.l and re-energise it.
It's interesting some of the differences in minimum speeds quoted for flow modifiers around the nacelle/wing junctions - they're quite significant.
To whoever it was suggested that Boeing 'invented' the nacelle strake or vortex generator - sounds like another re-writing of history to me
