Tunnel Testing Foils

[artnr110hb]

I have been reading thru old hydrodynamic papers where they test most of the hydro foils in wind tunnels, the results seem to good to be true (stall angles).
Will a foil stall at the same angle of attack in air as in its equivalent situation in water ?

 

[IRstuff]

It's a different fluid, isn't it?

TTFN
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[rb1957]

i guess that depends on how you determine "equilvalent" ?

if you're scaling by Reynold's number then i'd expect the foil would stall at the same angle in both flows (ie air and water)

but then maybe mixed media (air in water, leading to cavitation) might make a difference ...

but i guess it's a pretty good theory if we can make predictions and see them realised in tests, no?
and you're complaining that the match is too good ?? so it's either ...
a) the theory is spot on,
b) the theory is close, but there some minor plus and minus effects happening (which make it look good),
c) the theory is a crock and the experiments were just lucky,
d) the experimenters cooked their results

Quando Omni Flunkus Moritati