Wavelet analysis of transonic buffet on a two-dimensional airfoil with vortex generators

Toshinori Kouchi, Shingo Yamaguchi, Shunske Koike, Tsutomu Nakajima, Mamoru Sato, Hiroshi Kanda, Shinichiro Yanase

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

We visualized the shock buffets on a two-dimensional transonic airfoil with and without vortex generators (VGs) by using a fast-framing focusing schlieren imaging. The focusing schlieren visualization showed that the flow three-dimensionality around the airfoil became remarkable with installing the VGs. This implies that narrow depth of focus of imaging systems was a key to accurately capture the characteristics of the shock oscillation due to the buffet for the cases with VGs. The time-resolved imaging also revealed that non-periodic components were included in the shock oscillation due to the buffet for the cases with VGs. This prevented Fourier analysis from being applied. We used wavelet analysis to extract the characteristic of the shock oscillation for the cases with VGs. The wavelet spectrograms revealed that the low-frequency oscillation having the buffet frequency was still included intermittently in the shock oscillation even when VG controlled the buffet. The rate of appearing the low-frequency oscillation increased with increasing both the interval between VGs and the angle of attack.

Original languageEnglish
Article number166
JournalExperiments in Fluids
Volume57
Issue number11
DOIs
Publication statusPublished - Nov 1 2016

Fingerprint

vortex generators
transonic flow
Wavelet analysis
airfoils
Airfoils
wavelet analysis
Vortex flow
shock
oscillations
low frequencies
Imaging techniques
Fourier analysis
spectrograms
angle of attack
Angle of attack
Imaging systems
installing
Visualization
intervals

ASJC Scopus subject areas

  • Computational Mechanics
  • Mechanics of Materials
  • Physics and Astronomy(all)
  • Fluid Flow and Transfer Processes

Cite this

Wavelet analysis of transonic buffet on a two-dimensional airfoil with vortex generators. / Kouchi, Toshinori; Yamaguchi, Shingo; Koike, Shunske; Nakajima, Tsutomu; Sato, Mamoru; Kanda, Hiroshi; Yanase, Shinichiro.

In: Experiments in Fluids, Vol. 57, No. 11, 166, 01.11.2016.

Research output: Contribution to journalArticle

Kouchi, Toshinori ; Yamaguchi, Shingo ; Koike, Shunske ; Nakajima, Tsutomu ; Sato, Mamoru ; Kanda, Hiroshi ; Yanase, Shinichiro. / Wavelet analysis of transonic buffet on a two-dimensional airfoil with vortex generators. In: Experiments in Fluids. 2016 ; Vol. 57, No. 11.
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