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Hi Metro,
Yep, I have read the Mitsubishi paper, and their goal was to make their wing work better. They had a side benefit of a small amount of drag reduction, side benefit. The EVO is probably somewhat dangerous at speed, without the downforce from the wing, and the VG's.
The aircraft people use them further forward. On most commercial aircraft I have been on one can see the VG's just behind the thickest part of the wing. Yea, they are probably doing that to get them out of the 500 mph boundary layer, but just ahead of seperation at low speeds. The purpose in commercial aircraft is to provide a lower stall speed.
For cars the flow is thrown upward at the wind screen. The boundary layer is tight and laminar just before it goes over the roof on the typical car (not a Prius), but then through momentum jumps well up above the roof. If that upward momentum could be made sideways, the cross section of the boundary layer might be made less. I do not think this is a good use for a car like a Prius, but for cars with the more vertical windshields, yea it might work. This is kinda like those whale flukes, make the fluid flow go crosswise across the flat surfaces to keep it attached.
There is a thread on here which says Tubulence and Vorticity are good if they reduce the cross-section of the total disturbed air, ie the reduce effective vehicle cross section area. Otherwise, your just putting energy into wasteful flow.
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