Editing Magnus effect (section)

===Non-spinning cylinder===
[[Image:Potential cylinder.svg|thumb|200px|right|[[Streamlines, streaklines, and pathlines|Streamlines]] for the [[potential flow around a circular cylinder]] in a uniform flow.]]

The flow pattern is symmetric about a horizontal axis through the centre of the cylinder. At each point above the axis and its corresponding point below the axis, the spacing of streamlines is the same so velocities are also the same at the two points. Bernoulli's principle shows that, outside the [[boundary layers]], pressures are also the same at corresponding points. There is no lift acting on the cylinder.<ref>"From the symmetry of the streamlines it is clear that the velocity of the air is the same at corresponding points above and below the ball, ..."
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"From Bernoulli's equation we then deduce that the pressure at such corresponding points are equal and that the air exerts no upward or downward force on the ball by virtue of its motion; the dynamic lift is zero." Resnick and Halliday (1966), ''PHYSICS'', Section 18-5</ref>