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

1 Citation (Scopus)

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 - 2014
Event52nd Aerospace Sciences Meeting 2014 - National Harbor, United States
Duration: Jan 13 2014Jan 17 2014

Other

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

Fingerprint

Vorticity
Vortex flow
Airfoils
Fluxes
Planforms
Surface measurement
Arches
Angle of attack
Pressure measurement
Velocity measurement
Aspect ratio
Flow fields

All Science Journal Classification (ASJC) codes

  • Aerospace Engineering

Cite this

Buchholz, J. H. J., Eslam Panah, A., Akkala, J. M., Wabick, K. J., & Wojcik, C. J. (2014). Vorticity generation and transport on a plunging wing. In 52nd Aerospace Sciences Meeting American Institute of Aeronautics and Astronautics Inc..
Buchholz, James H J ; Eslam Panah, Azar ; Akkala, James M. ; Wabick, Kevin J. ; Wojcik, Craig J. / Vorticity generation and transport on a plunging wing. 52nd Aerospace Sciences Meeting. American Institute of Aeronautics and Astronautics Inc., 2014.
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Buchholz, JHJ, Eslam Panah, A, Akkala, JM, Wabick, KJ & Wojcik, CJ 2014, Vorticity generation and transport on a plunging wing. in 52nd Aerospace Sciences Meeting. American Institute of Aeronautics and Astronautics Inc., 52nd Aerospace Sciences Meeting 2014, National Harbor, United States, 1/13/14.

Vorticity generation and transport on a plunging wing. / Buchholz, James H J; Eslam Panah, Azar; Akkala, James M.; Wabick, Kevin J.; Wojcik, Craig J.

52nd Aerospace Sciences Meeting. American Institute of Aeronautics and Astronautics Inc., 2014.

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

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AU - Buchholz, James H J

AU - Eslam Panah, Azar

AU - Akkala, James M.

AU - Wabick, Kevin J.

AU - Wojcik, Craig J.

PY - 2014

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N2 - 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.

AB - 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.

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M3 - Conference contribution

BT - 52nd Aerospace Sciences Meeting

PB - American Institute of Aeronautics and Astronautics Inc.

ER -

Buchholz JHJ, Eslam Panah A, Akkala JM, Wabick KJ, Wojcik CJ. Vorticity generation and transport on a plunging wing. In 52nd Aerospace Sciences Meeting. American Institute of Aeronautics and Astronautics Inc. 2014