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Vortex force map method for viscous flows of general airfoils

Published online by Cambridge University Press:  11 December 2017

Juan Li
Affiliation:
Department of Engineering Mechanics, Tsinghua University, Beijing 100084, PR China Institute of Aeroengine, Tsinghua University, Beijing 100084, PR China
Zi-Niu Wu*
Affiliation:
Department of Engineering Mechanics, Tsinghua University, Beijing 100084, PR China Institute of Aeroengine, Tsinghua University, Beijing 100084, PR China
*
Email address for correspondence: ziniuwu@tsinghua.edu.cn

Abstract

In a previous paper, an inviscid vortex force map approach was developed for the normal force of a flat plate at arbitrarily high angle of attack and leading/trailing edge force-producing critical regions were identified. In this paper, this vortex force map approach is extended to viscous flows and general airfoils, for both lift and drag forces due to vortices. The vortex force factors for the vortex force map are obtained here by using Howe’s integral force formula. A decomposed form of the force formula, ensuring vortices far away from the body have negligible effect on the force, is also derived. Using Joukowsky and NACA0012 airfoils for illustration, it is found that the vortex force map for general airfoils is similar to that of a flat plate, meaning that force-producing critical regions similar to those of a flat plate also exist for more general airfoils and for viscous flow. The vortex force approach is validated against NACA0012 at several angles of attack and Reynolds numbers, by using computational fluid dynamics.

Type
JFM Papers
Copyright
© 2017 Cambridge University Press 

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