Lift at High Angles of Attack

  • Thread starter OrangeDog
  • Start date
  • #1
117
43

Main Question or Discussion Point

I need a reference for the exact solution for lift at high angles of attack, when an airfoil behaves like a flat plate. I am pretty sure the theoretical solution is CL = 2 sin(α)*cos(α) based on two papers I read on lift through 180 degrees angle of attack, but I cant find in any of my books where this is stated. This would also be consistent with the small angle approximation for flat plate lift, as the cosine term becomes 1 and the sin term equals α.

See the Sandia publication:
Aerodynamic Characteristics of Seven Symmetrical Airfoil Sections Through 180-Degree Angle of Attack for Use in Aerodynamic Analysis of Vertical Axis Wind Turbines"
 

Answers and Replies

  • #2
boneh3ad
Science Advisor
Insights Author
Gold Member
3,071
741
Have you checked a source like Theory of Wing Sections by Abbott and von Doenhoff? I don't recall off the top of my head if this is covered in there and my copy is at home, not with me at work, but it would probably be the first place I would look.
 
  • #3
117
43
Im at work now and cant check. ToWS only covers up to stall for their studies so I doubt it would be in there. I checked von Mises book "Theory of Flight" (my favorite aeronautics book by the way) and it only used the small angle approximation. For the life of me I cant remember where I found the high AoA solution...
 
  • #4
boneh3ad
Science Advisor
Insights Author
Gold Member
3,071
741
Yeah, basically all of my aeronautics books that don't involve compressible flow are at home right now or I'd do a quick flip through them.

On the other hand, if you were looking for sources on waves, compressible flows, hydrodynamic stability, or turbulence, then my stash of books at work would be of some help. Alas, you are not.
 
  • #5
117
43
My line of work is strictly pertaining to IC flows :( I just need to compare the theoretical solution with some data.
 

Related Threads on Lift at High Angles of Attack

Replies
1
Views
3K
Replies
0
Views
2K
Replies
2
Views
2K
Replies
5
Views
435
  • Last Post
Replies
1
Views
4K
  • Last Post
Replies
0
Views
6K
  • Last Post
Replies
1
Views
3K
  • Last Post
Replies
1
Views
2K
  • Last Post
Replies
10
Views
8K
Top