Unsteady vortex flows and buffeting of a low sweep delta wing

G S Taylor, I Gursul

Research output: Contribution to conferencePaper

12 Citations (Scopus)

Abstract

An experimental study was conducted to understand the unsteady vortex flows and buffeting response of a nonslender delta wing with 50° leading edge sweep angle. Particle Image Velocimetry (PIV) and Laser Doppler Velocimetry (LDV) measurements, surface flow visualization, force balance measurements, and wing-tip acceleration measurements were used. Weak vortex breakdown observed at low incidences is replaced by a conical breakdown with large unsteadiness with increasing incidence. However, the maximum buffeting occurs prior to the stall, after the vortex breakdown has reached the apex of the wing. The largest velocity fluctuations near the wing surface are observed along the reattachment line. Hence, the shear layer reattachment, rather than the vortex breakdown phenomenon, is the most important source of increasing buffet in the pre-stall region as incidence is increased. Velocity fluctuations near the wing surface in the reattachment region exhibit 'dual-peak' frequency spectra. With further increase in incidence, the shear layer reattachment fails resulting in very low velocity fluctuations near the wing surface and a precipitous fall in the rms wing tip acceleration.
Original languageEnglish
Pages6627-6635
Number of pages9
Publication statusPublished - 2004
EventAIAA - Reno, NV, USA United States
Duration: 1 Jan 2004 → …

Conference

ConferenceAIAA
CountryUSA United States
CityReno, NV
Period1/01/04 → …

Fingerprint

buffeting
swept wings
delta wings
vortex breakdown
wings
attachment
incidence
wing tips
vortices
shear layers
leading edge sweep
sweep angle
acceleration measurement
flow visualization
particle image velocimetry
low speed
apexes
breakdown
lasers

Keywords

  • Wind tunnels
  • Wings
  • Reynolds number
  • Unmanned vehicles
  • Vortex flow
  • Unsteady flow
  • Correlation methods

Cite this

Taylor, G. S., & Gursul, I. (2004). Unsteady vortex flows and buffeting of a low sweep delta wing. 6627-6635. Paper presented at AIAA, Reno, NV, USA United States.

Unsteady vortex flows and buffeting of a low sweep delta wing. / Taylor, G S; Gursul, I.

2004. 6627-6635 Paper presented at AIAA, Reno, NV, USA United States.

Research output: Contribution to conferencePaper

Taylor, GS & Gursul, I 2004, 'Unsteady vortex flows and buffeting of a low sweep delta wing' Paper presented at AIAA, Reno, NV, USA United States, 1/01/04, pp. 6627-6635.
Taylor GS, Gursul I. Unsteady vortex flows and buffeting of a low sweep delta wing. 2004. Paper presented at AIAA, Reno, NV, USA United States.
Taylor, G S ; Gursul, I. / Unsteady vortex flows and buffeting of a low sweep delta wing. Paper presented at AIAA, Reno, NV, USA United States.9 p.
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AB - An experimental study was conducted to understand the unsteady vortex flows and buffeting response of a nonslender delta wing with 50° leading edge sweep angle. Particle Image Velocimetry (PIV) and Laser Doppler Velocimetry (LDV) measurements, surface flow visualization, force balance measurements, and wing-tip acceleration measurements were used. Weak vortex breakdown observed at low incidences is replaced by a conical breakdown with large unsteadiness with increasing incidence. However, the maximum buffeting occurs prior to the stall, after the vortex breakdown has reached the apex of the wing. The largest velocity fluctuations near the wing surface are observed along the reattachment line. Hence, the shear layer reattachment, rather than the vortex breakdown phenomenon, is the most important source of increasing buffet in the pre-stall region as incidence is increased. Velocity fluctuations near the wing surface in the reattachment region exhibit 'dual-peak' frequency spectra. With further increase in incidence, the shear layer reattachment fails resulting in very low velocity fluctuations near the wing surface and a precipitous fall in the rms wing tip acceleration.

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