Dynamic stall discussion

[ACE-OF-ACES]

Originally Posted by Verhängnis

From my understanding a dynamic stall is when the Wing (Airfoil) changes Angle of attack so dramatically that the leading edge creates turbulent, fast moving airflows (Vortex's) which travel over the top of the wing created an increased lower pressure momentarily increasing lift cooeficient but once the vortex has passed the wing incurs a normal stall where there is not enough airflow over the airfoil to generate lift.

That follows the wiki definition I provided a few pages back.. but the wiki also included a reference for that [22] which expanded on that definition to point out that a lot of the dynamic part of it had to do with the dynamic nature of the atmosphere (wind vector)..

So it appears that an accelerated and dynamic stall share the following

1) load factor > 1g
2) stalls at higher speeds than normal stall speed (1g LF)

And what sets them apart is simply the rate of change in the AoA.. Which is probably why they call it dynamic?

But both will stall at the same critical AoA.. Just the dynamic will experience a brief increase in lift just before the stall.. due to the vortex movement.

So the question is how brief is brief?

Are we talking tens of seconds or tens of Millie seconds? If the later, than it is not worth adding the additional math to simulate the brief increase in lift because it will go un-noticed to the sim pilot. That is to say, in the real world an instrumented plane under test might notice (log the data) the Millie second spike of increased lift.. But the human won't.. So no need to simulate it IMHO.