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Effect of amplitude and mean angle-of-attack on the boundary layer of an oscillating aerofoil

Soltani, M. R ; Sharif University of Technology | 2008

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  1. Type of Document: Article
  2. DOI: 10.1017/S0001924000002670
  3. Publisher: Royal Aeronautical Society , 2008
  4. Abstract:
  5. Extensive experiments were conducted to study the effect of various parameters on the surface pressure distribution and transition point of an aerofoil section used in a wind turbine blade. In this paper details of the variation of transition point on the aforementioned aerofoil are presented. The aerofoil spanned the wind-tunnel test section and was oscillated sinusoidally in pitch about the quarter chord. The imposed variables of the experiments were free stream velocity, amplitude of motion, mean angle-of-attack, and oscillation frequency. The spatial-temporal progressions of the leading-edge transition point and the state of the unsteady boundary-layer were measured using eight closely-spaced, hot-film sensors (HFS). The measurements show that: (i) Reduced frequency has a pronounced effect on the variations of the transition point. (ii) There exists a hysteresis loop in the dynamic transition location and its shape varies with the reduced frequency and mean angle-of-attack
  6. Keywords:
  7. Aerodynamics ; Boundary layers ; Transition flow ; Turbomachine blades ; Wind tunnels ; Wind turbines ; Dynamic transitions ; Free-stream velocity ; Oscillation frequency ; Spatial temporals ; Surface pressure distribution ; Unsteady boundary layer ; Wind tunnel tests ; Wind turbine blades ; Angle of attack
  8. Source: Aeronautical Journal ; Volume 112, Issue 1138 , 2008 , Pages 705-713 ; 00019240 (ISSN)
  9. URL: https://www.cambridge.org/core/journals/aeronautical-journal/article/abs/effect-of-amplitude-and-mean-angleofattack-on-the-boundary-layer-of-an-oscillating-aerofoil/5738B78827B1E813209F4796173C4C77