Structure of a Perturbed Trailing Vortex

The flow structure of a trailing vortex from an oscillating wing provides unique insight into the unsteady physics of vortices. These oscillations can lead to dramatic changes in vortex structure which can include large unsteady fluctuations, vortex wandering and, in some cases, lead to vortex breakdown. The effect of wing oscillations on the development and evolution of the tip-vortex is depicted through volumetrically reconstructed images of axial vorticity and axial velocity deficit, colorized with levels of circulation and swirl ratio. The interplay between these flow features govern the response of the vortex from a wing subjected to unsteady oscillation and directly impact the impingement of the vortex on a follower wing or aircraft. 

The structure of a vortex from an oscillating wing and its interaction with a follower wing has been investigated. The unsteady response of the vortex from an oscillating wing will dictate the physics of its interaction with a secondary, follower wing. The steady and unsteady loading experienced by the follower wing is directly tied to the flow physics of the incident vortex and has important consequences for aircraft safety and formation flight. Volumetrically reconstructed images of axial vorticity are presented with additional highlighted cross-sectional slices. The flow structure depicts one interaction mechanism in which the incident vortex impinges on the tip of the follower wing. The positioning of the incident vortex induces an opposite signed tip vortex along the follower wing. The two vortices form a dipole whose position oscillates about the tip of the follower wing.