Ball moving above the critical speed. Flow necessarily symmetrical.
The boundary layer now clings much further round the ball. The wake is now
narrower, but the pressure in it immediately behind the ball is higher than
in the first diagram, with the result that the retarding force (coefficient)
is much less.
The boundary layer can also be extended in this way (for lower speeds) by
slight surface roughness on the first half of the ball, and the resistance
force similarly reduced.
(The drawing is not to scale : the thickness of the boundary layer is
exaggerated in order to show it.)