Help with calculation of drag coefficent

Hi!

I´m having trouble with the obtention of the drag coefficent for a cylinder immersed in a flow. I´ve been able to read the tutorial of this link:

www.comsol.com/showroom/downlo...e/models.mph.cylinder_flow.pdf

As you can see, the drag coefificent can be calculated this way:

-reacf(u)*2/(spf.rho*U_mean^2*0.1)

Obviously, I´ve adjusted the equation above in my problem but the drag coefficient doesn´t converge to a value. Don´t get confused, there are no vortexes in the back of the cylinder for this analysis.


Thanks.