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Experimental investigation of a supercritical airfoil boundary layer in pitching motion

Masdari, M ; Sharif University of Technology | 2017

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  1. Type of Document: Article
  2. DOI: 10.1007/s12206-016-1221-3
  3. Publisher: Korean Society of Mechanical Engineers , 2017
  4. Abstract:
  5. In this study, the boundary layer velocity profile on the upper surface of a supercritical airfoil in a forced sinusoidal pitching motion was measured and experimentally investigated. Measurements were performed using a boundary layer rake, including total pressure tubes positioned at 25 % of the chord far from the leading edge on the upper surface. For static measurements, the effects of the angle of attack between −3° and 14° and free-stream velocity between 40 m/s and 70 m/s were investigated; for dynamic measurements, the effects of oscillation amplitude variation between ±3° and ±10°, reduced frequency from 0.007 to 0.0313, and mean angle of attack between −3° and 6° were studied during one oscillation cycle. Results indicated that the boundary layer thickness decreased in upstroke motion. Increasing the oscillation frequency led to the extension of hysteresis loops. Fast Fourier transform was used on pressure signals to study the amplitude of the dominant frequency in the velocity profile. Spectral analysis showed that the dominant forced frequency of oscillation in the boundary layer and the amplitude of this frequency were varied by increasing the reduced frequency and other parameters. © 2017, The Korean Society of Mechanical Engineers and Springer-Verlag Berlin Heidelberg
  6. Keywords:
  7. Dominant frequency ; Hysteresis ; Pitching motion ; Supercritical airfoil ; Aerodynamics ; Airfoils ; Angle of attack ; Boundary layer flow ; Fast Fourier transforms ; Spectrum analysis ; Boundary layer thickness ; Boundary layer velocity ; Experimental investigations ; Frequency of oscillation ; Pitching motion ; Supercritical airfoils ; Unsteady boundary layer ; Boundary layers
  8. Source: Journal of Mechanical Science and Technology ; Volume 31, Issue 1 , 2017 , Pages 189-196 ; 1738494X (ISSN)
  9. URL: https://link.springer.com/article/10.1007/s12206-016-1221-3