[being.indraniil]

Hello friends and CFD Enthusiasts,

I have been struggling to work on one of the problems which involves simulation of a conventional NACA 0012 airfoil. Despite trying almost everything I haven't been able to match the simulation values with the experimental values (Ladson study, NASA). I have refined the mesh, run the simulation on structured mesh (0.2 million elements) and unstructured mesh (2.4 million elements) using the K-Omega and K-Epsilon turbulence models. I have even tried the Spallart Almaras model too. However, none of them have yielded favourable results.
For a Reynolds number of 1 Million,

The EXPERIMENTAL VALUE:
cl=0.5 approximately for the airfoil around 5° angle of attack.
cd=0.008
But the CFD analysis is only yielding,
cl=0.245
cd=-0.008

I have even ran an XFLR analysis at Re=1 Million. Even that value seemed fairly in agreement with the experimental values.

Can someone please suggest where I maybe going wrong?