trying to calculate the dragging force on a structure
 

Hi all !
I am trying to calculate the dragging force on a structure subject to a 70m/s wind. The geometry is quite simple : a cylinder base (1m diameter/0.2m height) and a hemispherical top (D=1m).
Reynolds is above 1E6 so I'm wondering what is the ideal settings in CFX in order to get a good and accurate result.
By hand, the dragging force is around 800N but the FEA calculus gives 300N. What should I do to get close to the real force (pressure) on the structure ?
Thanks.
J.