calculation of Hydrodynamic force on cylinder
 

I am trying to find out the hydrodynamic force on a circular cylinder. But I don't know how to do it. Can anone please tell me the procedure of computing the force on a cylinder? The cylinder is fixed the water is moving with a specified velocity through the inlet.....I need to know the procedure....There is no problem regarding the design module and mesh generation. The only problem is how to find out the force by FLUENT software...
Thanks in advance...