However, i think the results of a rotary test on our canard idea would
be hard to interpret due to the non-negligible, and mostly unknown
vorticity in the impinging stream that would be present due to repeated
passage through already disturbed air.
I see your point, and I agree with you while testing low AOA, but I
would imagine that the rotating fin could get "fresh" air as it
travels through the disk ('disk' being the circular plane formed as
the test fin travels around the center pivot point.) at higher AOA.
This is definitely the case with a hovering helicopter, but arguably,
we have a smaller blade.
For our application the performance parameter that is most difficult to
predict theoretically, and therefore that is of most interest
experimentally, is the position on the leeward surface of the canard
where the (vortex) flow becomes separated. Unfortunately, the
separation position is quite sensitive to the vorticity in the impinging
stream, so to get results meaningful to the control problem from a
rotary track test we would need some method of calibrating the incident
vorticity and some theoretical way of scaling the results to zero
Would you imagine that smooth air will have a significant effect on
the lift curve, or is this a small "correction" added to the overall
Could you point me to an explanation of incident vorticity?
At this point i don't know how to do that scaling, and i expect that it
is not easy.
(But i don't _know_ that it is not easy. It _might_ be easy ;)
If it turned out that the scaling was easy, then we'd have a really
nifty idea, and possibly a significant new insight into aerodynamics.
My thought is that there must be a way to provide clean air to the fin
as it spins... I'll keep thinking about it.
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