Vortex Generation

The origin of counter-rotating wing tip vortices is a direct and automatic consequence of the generation of lift by a wing. Lift is generated by the creation of a pressure differential over the wing surface. The lowest pressure occurs over the upper wing surface and the highest pressure under the wing. This pressure differential triggers the roll up of the airflow aft of the wing resulting in swirling air masses trailing downstream of the wing tips. After the roll up is completed, the wake consists of two counter-rotating cylindrical vortices. For further detail, see the separate article: Induced Drag.