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

Published online by Cambridge University Press:  03 February 2016

M. R. Soltani  and
A. Bakhshalipour
M. R. Soltani
Affiliation:
Sharif University of Technology, Department of Aerospace Engineering, Tehran, Iran
A. Bakhshalipour
Affiliation:
Sharif University of Technology, Department of Aerospace Engineering, Tehran, Iran
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Abstract

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.

Type
Research Article
Information
The Aeronautical Journal , Volume 112 , Issue 1138 , December 2008 , pp. 705 - 713
Copyright
Copyright © Royal Aeronautical Society 2008 

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