Definition
Pairs of small, tube-shaped swirls of air spinning in opposite directions, produced by vortex generators on a wing or control surface. Each pair re-energizes the boundary layer by mixing fast-moving air from above into the slower air clinging to the surface, delaying flow separation and stall.
Plain English
Tiny twin air-swirls that spin in opposite directions and stir up the air close to the wing's skin. This stirring keeps the airflow attached to the wing longer, so the wing keeps flying instead of stalling.
Context Anchor
Seen in aerodynamics discussions of vortex generators, airflow separation, stalls, and control effectiveness.
Derivation
Counter rotating means turning in opposite directions. Cylindrical means tube-shaped. Vortex comes from the Latin vortex/vertex, meaning a whirl or eddy. Together: tube-shaped whirls spinning opposite ways.
Why Pilots Care
These vortices produce wake turbulence that can roll or pitch a following aircraft, creating serious hazard especially when a light aircraft follows a heavy one.
Grounding Statement
Picture two small spinning tubes of air lying side by side along the top of the wing, one turning clockwise and the other counter-clockwise -- each one dragging fast air down onto the wing surface.
Intuition Check
Do not picture solid cylinders. These are moving rolls of air. Do not read counter rotating as the airplane turning the other way. It means the two air rolls spin in opposite directions.
Example Sentence 1
The vortex generators along the leading edge produce counter rotating cylindrical vortices that delay the stall to a higher angle of attack.
Example Sentence 2
Controllers increased spacing on final approach because the arriving airliner was generating strong counter rotating cylindrical vortices.