Vorticity generation and transport on a plunging wing

James H.J. Buchholz, Azar Eslam Panah, James M. Akkala, Kevin J. Wabick, Craig J. Wojcik

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Two-component particle image velocimetry and surface pressure measurements are used to characterize the flow field over a plunging nominally two-dimensional at-plate airfoil at zero geometric angle of attack, and a finite wing with rectangular planform and a semi- aspect-ratio sAR = 2. Phase-averaged horizontal and vertical planes of PIV data are used to reconstruct a three-dimensional volume in which the evolution of the vortex structure is rendered, and vorticity transport is quantified within a chordwise planar control volume bounded by the at plate surface, and containing the leading-edge vortex. It is shown that, for the two-dimensional airfoil, generation of secondary vorticity of opposite sign to the leading-edge vortex occurs at a rate of approximately half that of the leading-edge shear layer flux, suggesting that entrainment of this vorticity into the leading-edge vortex has a significant impact on the strength of the vortex. Also, spanwise convection of vorticity has a non-negligible impact on control-volume circulation during the second half of the stroke. In the case of the finite wing, the initial development of the leading-edge vortex is qualitatively similar to that of the nominally two-dimensional case; however, through the mid-portion of the stroke, the leading-edge vortex rapidly evolves into an arch structure as it convects along the chord, as seen in previous studies. In contrast to the case of the nominally two-dimensional airfoil, spanwise flow acts to significantly deplete the circulation within the leading-edge vortex. The difference between control-volume circulation and the sum of the integrated convective boundary fluxes suggests that the fraction of the total vorticity flux supplied by the finite wing surface beneath the leading-edge vortex is similar to that of the two-dimensional case.

Original languageEnglish (US)
Title of host publication52nd Aerospace Sciences Meeting
PublisherAmerican Institute of Aeronautics and Astronautics Inc.
ISBN (Electronic)9781624102561
StatePublished - Jan 1 2014
Event52nd Aerospace Sciences Meeting 2014 - National Harbor, United States
Duration: Jan 13 2014Jan 17 2014

Publication series

Name52nd Aerospace Sciences Meeting

Other

Other52nd Aerospace Sciences Meeting 2014
CountryUnited States
CityNational Harbor
Period1/13/141/17/14

All Science Journal Classification (ASJC) codes

  • Aerospace Engineering

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    Buchholz, J. H. J., Panah, A. E., Akkala, J. M., Wabick, K. J., & Wojcik, C. J. (2014). Vorticity generation and transport on a plunging wing. In 52nd Aerospace Sciences Meeting (52nd Aerospace Sciences Meeting). American Institute of Aeronautics and Astronautics Inc..