drag coefficient with k-eps model

Mark

Hi,

I'm calculating the 2D-flow over a NACA0015 profil with standard k-eps turbulence model. yplus values are between 20 and 100 along the chord.

I'm am looking for an explanation for the following observation.

Below stall angle the lift coefficient fits quite well to measurements. But the drag coefficient is far to high. At zero angle of attack some papers report a drag coefficent of approx. 0.0068. My calculated value is at 0.01.

I think I understood why I can't expect too much beyond stall angle, but what might be the reason for that difference in drag?

Best regards, Mark