I seem to remember the effect being called the 'Coander' effect, not sure of the spellung
It is used on helicopters enabling the tail boom of some heavy helos to off load the tail rotor by giving an element of lift.
The Notar also uses this effect to provide a 'NO Tail Rotor' aircraft. This uses a variable slot along the length of the tail boom which is fed by low pressure air from a fan in the after avionics compartment. By varying the slot the lift produced by the circular section tail boom can be altered thus assisting the steering duct at the back.
However, as helos are, probably, the worlds worst aerodynamic beasties, coupled with the fact that the majority of drag effects felt by these uses are infact perpendicular to the flight path, drag is not so much of a factor.
Sticking curry house furry wallpaper to the underside of a wing will dramatically increase drag, requireing an increase in thrust for any given value of Cl.
