much smoother Cd and Cl vs. angles of attack compared to experimental results
 

Hi Guys,

I am modeling a 2-d incompressible air flow over a quarter cylindrical body (the shape is a quarter of a circular disk). The inlet velocity is 6.1m/s and I am using SA turbulence model for the simulation. My interest is the Cd and Cl over a wide range of angles of attack, -10 degree to 50 degrees. For all these angles of attack, steady state solutions can be attained. I compared the values of Cd and Cl with existing experimental data and found very nice agreement for all of them. The only thing bothers me is that there is a sharp rise at 30 degrees of angle for Cl and Cd for the experimental data while the CFD value transitions quite smoothly. Does anyone have any idea what is going on here?

Thanks a lot.