Slowrotor,
Thanks for taking the time to engage in the discussion, transition on helicopter rotors is something I have spent a long time working on and so I have quite a good understanding of what’s involved! ...I hope!
With regards the supercritical aerofoils, they are simply aerofoils that have been designed with low upper surface curvature in order to minimise the strength of the shocks created a high subsonic mach numbers without having to resort to very low thickness-to-chord ratios, which are impractical for real aircraft. I have attached a picture from Georgia Tech's website that show the differences between the geometry and pressure distributions of a normal NACA aerofoil (Left) at high subsonic mach numbers and a supercritical one (Right).
Hope this helps
CRAN
Zeeoo,
2D is shorthand for two-dimensional and 3D is shorthand for three-dimensional. In aerodynamic terms we usually refer to things as being two-dimensional phenomena when they don't vary with span, such as the pressure distribution around a constant section, constant chord infinite span wing. A three-dimensional phenomenon is one which does vary with span, such as the roll-up process of the tip vortex around a wing or rotor tip (its effect becomes less as you move inboard).
With regards laminar flow in autorotation, there will probably not be much. But this will be due to the fact that the rotor is in forward flight (see my earlier post) not because it is in autorotation. Visualisations of the rotor wake in hover and steady forward flight look just a scary! Have a look at Richard Brown’s work at Imperial:
http://www.ae.ic.ac.uk/research/rotorcraft/
Hope this helps
CRAN