Let's imagine a ring sector (from a random planar face revolved 360deg). Is there a way to differentiate between the non-circumferential faces and the circumferential faces ? The available information are the centers of gravity, surfaces areas, volume centroid of the ring, a point on each surface and normals.
For instance, in the image above I would like to differentiate between the blue faces and the white ones. Please note that this ring has been made from a square face revolved but the geometry could come from any type of cross section. Any ideas?