I dont understand whats going on with the angle of attack?????

Dear whoever can help,

I have recently started using solidworks to model flow around an s809 aerofoil and my results for Cl and Cd are very different when i change the angle of attack by either changing the velocities in general setting or physically rotating the model!!!!!

I do not understand why this is the case.

If anyone has an answer or way to deal with it, or even suggestion as to which method i should use i would be very appreciative