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Vortex moment map for unsteady incompressible viscous flows

Published online by Cambridge University Press:  23 March 2020

Juan Li Open the ORCID record for Juan Li [Opens in a new window] ,
Yinan Wang Open the ORCID record for Yinan Wang [Opens in a new window] ,
Michael Graham Open the ORCID record for Michael Graham [Opens in a new window]  and
Xiaowei Zhao Open the ORCID record for Xiaowei Zhao [Opens in a new window]
Juan Li
Affiliation:
School of Engineering, The University of Warwick, Coventry CV4 7AL, UK
Yinan Wang
Affiliation:
School of Engineering, The University of Warwick, Coventry CV4 7AL, UK
Michael Graham
Affiliation:
Department of Aeronautics, Imperial College, London SW7 2BY, UK
Xiaowei Zhao*
Affiliation:
School of Engineering, The University of Warwick, Coventry CV4 7AL, UK
*
†Email address for correspondence: [email protected]
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Abstract

In this paper, a vortex moment map (VMM) method is proposed to predict the pitching moment on a body from the vorticity field. VMM is designed to identify the moment contribution of each given vortex in the flow field. Implementing this VMM approach in starting flows of a NACA0012 airfoil, it is found that, due to the rolling up of leading-edge vortices (LEVs) and trailing-edge vortices (TEVs), the unsteady nose-down moment about the quarter chord is higher than the steady-state value. The time variation of the unsteady moment is closely related to the LEVs and TEVs near the body and the VMM gives an intuitive understanding of how each part of the vorticity field contributes to the pitching moment on the body.

JFM classification

Vortex Flows: Vortex shedding Wakes/Jets: Separated flows
Type
JFM Papers
Information
Journal of Fluid Mechanics , Volume 891 , 25 May 2020 , A13
Copyright
© The Author(s), 2020. Published by Cambridge University Press

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