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Difficulty in understanding Coeff. of Drag of Airfoil

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Old   April 9, 2017, 02:38
Default Difficulty in understanding Coeff. of Drag of Airfoil
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Dear all,

I am finding difficulty in understanding the Coeff. of Drag and lift of a wing whose cross section is derived from Althaus AH 79-100A airfoil(link for coordinate file - The simulation was done in Star CCM+ R9 . The values obtained were,
Cd = 0.2811885068982537
Cl = 5.196364470423872
The dimensions of the wing are
Wing span (s) = 0.85417 m
Wing chord (c) = 0.0982m
Aspect ratio (AR) = 8.7
Angle of attack = 0 degrees
Air velocity = 30 m/s

Regarding mesh and physics continua

Mesh Base size = 0.014(prism layers and vol. controls were employed around wing body)
Physics model - K-epsilon.

My doubt is that whether the values obtained are correct or resemble to real time values and if so then why the Cd is so high?(i have attached the picture of the domain and wing so that you can have better understanding).If the values are not justifiable then what may be the possible causes of error.
Thank you in advance and your help is really appreciated.
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