Unsteady nature of vortex pair in formation flight

C. Chen, Z. Wang, Ismet Gursul

Research output: Contribution to conferencePaper


The interaction of trailing vortices from a leading wing with rigid and flexible downstream wings has been investigated experimentally in an open jet wind tunnel using force measurements, particle image velocimetry measurements, hotwire measurements and deformation measurements. Counter-rotating leading vortex has been found to have substantial meandering when it is close to the tip of the downstream wing. The leading vortex forms a pair with the vortex from the downstream wing, and then exhibits large displacements around the wing tip. This has been found to cause the largest lift fluctuations on the downstream wing. The meandering of the vortex pair occurs at the natural meandering frequency of the isolated vortex, with a low Strouhal number, and is not affected by the frequency of the wing bending oscillations if the downstream wing is flexible. While the displacement of the leading vortex is larger than that of the trailing vortex, time-dependent variations of the core radius, core vorticity and circulation are evident for the trailing vortex. In contrast, co-rotating vortices do not exhibit any increased meandering.

Original languageEnglish
Publication statusPublished - 2017
Event47th AIAA Fluid Dynamics Conference, 2017 - Denver, USA United States
Duration: 5 Jun 20179 Jun 2017


Conference47th AIAA Fluid Dynamics Conference, 2017
Country/TerritoryUSA United States

ASJC Scopus subject areas

  • Aerospace Engineering
  • Engineering (miscellaneous)


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