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On the dynamics of three-dimensional slung prisms under very low and high turbulence flows

Published online by Cambridge University Press:  07 March 2017

Y. Jin  and
L. P. Chamorro Open the ORCID record for L. P. Chamorro [Opens in a new window]
Y. Jin
Affiliation:
Mechanical Science and Engineering Department, University of Illinois, Urbana, IL 61801, USA
L. P. Chamorro*
Affiliation:
Mechanical Science and Engineering Department, University of Illinois, Urbana, IL 61801, USA Civil and Environmental Engineering Department, University of Illinois, Urbana, IL 61801, USA Aerospace Engineering, University of Illinois, Urbana, IL 61801, USA
*
†Email address for correspondence: lpchamo@illinois.edu
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Abstract

The distinctive pendulum-like oscillation and pitching patterns of cubic and rectangular slung prisms were inspected for two aspect ratios at various Reynolds numbers $Re$ under two free-stream turbulence levels. Systematic experiments were performed using high-resolution telemetry and hotwire anemometry to quantitatively characterize the dynamics of the prisms and the wake fluctuation. The results show that the dynamics of the prisms can be characterized by two distinctive regions depending on the prism shape. Specifically, in the case of cubic prisms the regions are defined by the growth rate of the pitching amplitude; whereas the dynamics of the rectangular prisms is more sensitive to the angle of attack. In particular, when the large side initially faces the flow, the regions are defined by the synchronization between the vortex shedding and pure oscillations under very low turbulence. When the smaller side initially faces the flow, the regions are defined by the equilibrium pitching position. Regardless of the geometry of the prism and flow condition the dominant oscillation frequency resulted as being close to the natural frequency of the small-amplitude pendulum-like oscillation.

JFM classification

Aerodynamics: Aerodynamics
Type
Papers
Information
Journal of Fluid Mechanics , Volume 816 , 10 April 2017 , pp. 468 - 480
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Copyright
© 2017 Cambridge University Press 

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