Quote:
Originally Posted by aerohead
*All these deflectors were tested and failed to produce a drag reduction.Some increased drag.
*The blown slot will work if you have a perpetual-motion device to produce the air volumes necessary.
*Ducts have been tested and they failed also.
What may work in an aeronautical application doesn't necessarily apply to a bluff body in ground proximity.And you need to be about 12-ft off the road surface to get out of ground effect.
*The truncated wing is Cd 0.58
*The truncated wing with turning vanes is Cd 0.28
*The unmutilated wing is Cd 0.006
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Yeah, I don't think the 'wake-filling' approach is the way to go here at all...
It is interesting that the turning vanes are an improvement over the truncated wing though. Perhaps in the case of a wing, the plain truncated case can't set up a stable recirculation behind it as you find with a ground vehicle?
OTOH an increase in drag compared to an unmutilated wing but a decrease in drag compared to a truncated wing
does sound promising if you aren't considering a full boat-tail
though
if the figures are indicative, it sounds like a kammback would work better. Extrapolating numbers from an airfoil in a free stream to a bluff body in ground effect is a bit sketchy though...