Highflyer wrote:

...

No. wingtip vortices are caused by downwash. Infinite wings don't have
wingtip vortices because they don't have ends, not because they don't have
downwash.


Wingtip vortices are caused by the pressure differential between the
lower and upper wing surface. The air moves from the lower to the
upper, around the wingtip. Wingtip vortices reduce lift because
they cause the pressure below the wingtip to be lower and above the
wingtip to be higher, than at points further inbound.

Conservation of angular momemtum causes the air to continue swirling
after the aircraft has passed. Once the pressure changes caused by
the passage of the aircraft have died out and the pressure restored to

ambient the net downward flow from the entire aircraft is equal to net
upward flow from the entire aircraft, provided the aircraft is in level
flight.
If the aircraft is climbing or diving the only net flow is that cuased
by the
displacement of the volume of the aircraft.

Those last two sentences are key.

Infinite wings lack wingtip vortices because they lack wingtips.

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FF