wrong drag and lift at high AoA
 

Hi,

i am running both URANS (2D and 3D) simulations on a s809 airfoil at very large AoA (ca. 60 degrees) and constantly over-predicting C-lift and C-drag.
I am a bit puzzled about it since i tried pretty much everything but i wanted to ask in her if some of you has been working with any type of bluff body flows (cylinders, flat plates at high AoA) and has been experiencing similar problems. In this article Pellegrino seems to have similar problems http://www.tara.tcd.ie/xmlui/bitstre...pdf?sequence=1

so i am starting to wonder if it is quite common to get wrong lift and drag values.
Thanks in advance