Airfoil wall roughness constant
 

Dear friends,

I did simulation on NACA0012 with 10 degree AOA. all my setup in fluent is correct and when i compared my results with nasa experiments i found:
the same pressure coefficient
my Cl=.65 but nasa=1
my cd=.054 but nasa=.006
i think it's related to [Roughness constant of alluminum] material in fluent, but what should i define it to get the same result??