Lift and drag force

Hi all,

I am simulating a 2D, turbulent flow over the airfoil. In the post-processing level, I do not know how to get lift and drag forces applying on the airfoil.

To compute reaction forces, As far as I'm concerned, weak constraints should be implemented. However I have not found out how to access weak constraints in the software and how should I use them. It would be really nice if someone can share his knowledge and experience.

Thanks,
Shayan