Thanks for all your help. I found Cp at all the points of pressure measurement, multiplied by cos of the angle of rotation, plotted the product versus angle of rotation and integrated from 0 to pi.
Turns out the drag coefficient for the large cylinder is about 0.71 and 1.07 for the small...
I'm trying to obtain the drag force acting on a smooth cylinder at the exit plane of a wind tunnel. I took measurements of pressure at regular degree intervals around the cylinder.
The pressure readings are in inches of water, and I know the freestream velocity and the stagnation pressure...