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A theoretical investigation of enhanced lift in the presence of thin aerofoil stall

Published online by Cambridge University Press:  04 July 2016

W. W. H. Yeung  and
G. V. Parkinson
W. W. H. Yeung
Affiliation:
School of Mechanical and Production EngineeringNanyang Technological University, Singapore
G. V. Parkinson
Affiliation:
Department of Mechanical EngineeringUniversity of British Columbia, Vancouver, Canada
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Abstract

A theoretical study is presented for the investigation of a potential-flow model for enhancing lift over a flat-plate aerofoil experiencing thin aerofoil stall. Rather than suppressing the leading-edge separation, flow is assumed to separate tangentially at the leading edge and made to reattach smoothly at the tip of a forward-facing fence joining the plate tangentially on its upper surface to avoid any unnecessary stagnated flow. The length of the fence and its location from the leading edge form two geometrical parameters. At any positive angle of attack, the resulting bounding streamline emanating from the leading edge and terminating at the tip of the fence is simulated by using suitable mathematical singularities subject to boundary conditions such as attaining a finite velocity at each critical point of the conformal mapping involved, and the condition of finite pressure gradient at reattachment, when applicable. Computational results from varying these two geometrical parameters indicate that the lift from each model is enhanced, as compared with the attached flow model around a simple flat plate and the original separated flow model by Kirchhoff.

Type
Research Article
Information
The Aeronautical Journal , Volume 103 , Issue 1023 , May 1999 , pp. 237 - 244
Copyright
Copyright © Royal Aeronautical Society 1999 

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