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Nonlinear fluid damping of elastically mounted pitching wings in quiescent water

Published online by Cambridge University Press:  22 July 2021

Yuanhang Zhu*
Affiliation:
Center for Fluid Mechanics, School of Engineering, Brown University, Providence, RI 02912, USA
Varghese Mathai
Affiliation:
Department of Physics, University of Massachusetts, Amherst, MA 01003, USA
Kenneth Breuer
Affiliation:
Center for Fluid Mechanics, School of Engineering, Brown University, Providence, RI 02912, USA
*
Email address for correspondence: yuanhang_zhu@brown.edu

Abstract

We experimentally study the nonlinear fluid damping of a rigid but elastically mounted pitching wing in the absence of a free-stream flow. The dynamics of the elastic mount are simulated using a cyber-physical system. We perturb the wing and measure the fluid damping coefficient from damped oscillations over a large range of pitching frequencies, pitching amplitudes, pivot locations and sweep angles. A universal fluid damping scaling is proposed to incorporate all these parameters. Flow fields obtained using particle image velocimetry are analysed to explain the nonlinear behaviours of the fluid damping.

Type
JFM Rapids
Copyright
© The Author(s), 2021. Published by Cambridge University Press

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Zhu et al. supplementary movie

PIV flow field measurements for an unswept wing undergoing prescribed sinusoidal pitching motions in quiescent water

Download Zhu et al. supplementary movie(Video)
Video 8.8 MB