In the figure above, a bullet is viewed from behind and is assumed to have right-handed twist. Additionally, the bullet should have an angle of yaw, its longitudinal axis should be inclined to the left. Then there is a component of the flowfield velocity vn, perpendicular to the bullet´s axis of symmetry.
Due to bullet spin and air molecules adhering to the bullet´s surface, the flowfield in the vicinity of the bullet becomes asymmetric. Air stream velocity and the rotational velocity of the body subtract at point A and add at point B (see above figure). However, according to Bernoulli´s rule (see any elementary physics book), this coincides with a pressure difference. A higher pressure at A and a lower pressure at B give rise to a downward directed force, which is called the Magnus force FM.
