Unsteady aerodynamics analysis and modelling of a Slingsby Firefly aircraft: Detached-Eddy Simulation model and flight test validation

A. F. Neves, N. J. Lawson, C. J. Bennett, B. Khanal, R. I. Hoff

Research output: Contribution to journalArticle

Abstract

This paper presents unsteady stall characteristics of a Slingsby T67M260 Firefly light aircraft from both a computational fluid dynamics (CFD) half model and flight tests. Initial results from the steady CFD, based on a RANS k−ω SST turbulence model, established the critical angle of attack of the stall to be αstall=16, with a maximum lift coefficient of CLmax=1.2. Comparisons with straight and level flight test data were comparable up to α=12 – 14, with the increasing deviation at higher α attributed to the effect of the propeller slipstream under these flight conditions. The RANS CFD model was then extended to an unsteady Detached-Eddy Simulation (DES) model for three angles of attack at pre-stall and stall condition (α=14, 16, 18), with analysis of the vortex shedding frequency. Further comparisons were then made with flight test data taken using on-board accelerometers and wing tuft surface flow visualization, at a stalled condition at equivalent α. These unsteady CFD data established a dominant shedding frequency ranging from 11.7 Hz – 8.74 Hz with increasing α and a Strouhal number based on wing chord of St = 0.11, which when compared to flight test accelerometer spectra matched within 2.9% of the measured frequency.

Original languageEnglish
Article number106179
JournalAerospace Science and Technology
Volume106
Early online date7 Sep 2020
DOIs
Publication statusE-pub ahead of print - 7 Sep 2020

Keywords

  • Buffet frequency
  • CFD
  • Detached-Eddy Simulation
  • Flight test
  • Stall
  • Strouhal number

ASJC Scopus subject areas

  • Aerospace Engineering

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