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Freestream turbulence effects on the aerodynamics of an oscillating square cylinder at the resonant frequency

Freestream turbulence effects on the aerodynamics of an oscillating square cylinder at the resonant frequency
Freestream turbulence effects on the aerodynamics of an oscillating square cylinder at the resonant frequency
Flow past a bluff body in freestream turbulence can substantially change the flow behaviour compared to that in smooth inflow. This paper presents the study of wake flow and aerodynamics of an oscillating square cylinder at the resonant frequency in freestream turbulence, with the integral length not greater than the cylinder side and the turbulence intensity not greater than 10\%. Large eddy simulations (LES) in the Cartesian grid using the Immersed Boundary Method (IBM) technique embedded in a FVM solver, together with an efficient synthetic turbulent inflow generator implemented in an in-house parallel FORTRAN code (Chen et al, 2020, Journal of Fluids and Structures 2020) are used for the study. The results are compared with those for smooth inflow, and relevant data published in the literature. The key findings are: the freestream turbulence conditions evidently reduces the local turbulent scales and fluctuations in the shear layer compared to in smooth flow, as small scale freestream turbulence breaks down cylinder-generated larger scale eddies and weakens them; but does not evidently affect the vortex shedding frequency, or the length of the recirculation region behind the cylinder. This suggests negligible change of drag coefficient compared to in smooth inflow. Moreover, this is because the vortex shedding is dominated by the forced oscillation at the resonance frequency, and the turbulence intensity is small.
integral length scale, oscillating square cylinders, shear layer, turbulence intensity, wake
2311-5521
Chen, Yongxin
634612c1-2eee-429e-b9f5-cea9fc105ffc
Djidjeli, Kamal
94ac4002-4170-495b-a443-74fde3b92998
Xie, Zheng-Tong
98ced75d-5617-4c2d-b20f-7038c54f4ff0
Chen, Yongxin
634612c1-2eee-429e-b9f5-cea9fc105ffc
Djidjeli, Kamal
94ac4002-4170-495b-a443-74fde3b92998
Xie, Zheng-Tong
98ced75d-5617-4c2d-b20f-7038c54f4ff0

Chen, Yongxin, Djidjeli, Kamal and Xie, Zheng-Tong (2022) Freestream turbulence effects on the aerodynamics of an oscillating square cylinder at the resonant frequency. Fluids, 7 (329), [329]. (doi:10.3390/fluids7100329).

Record type: Article

Abstract

Flow past a bluff body in freestream turbulence can substantially change the flow behaviour compared to that in smooth inflow. This paper presents the study of wake flow and aerodynamics of an oscillating square cylinder at the resonant frequency in freestream turbulence, with the integral length not greater than the cylinder side and the turbulence intensity not greater than 10\%. Large eddy simulations (LES) in the Cartesian grid using the Immersed Boundary Method (IBM) technique embedded in a FVM solver, together with an efficient synthetic turbulent inflow generator implemented in an in-house parallel FORTRAN code (Chen et al, 2020, Journal of Fluids and Structures 2020) are used for the study. The results are compared with those for smooth inflow, and relevant data published in the literature. The key findings are: the freestream turbulence conditions evidently reduces the local turbulent scales and fluctuations in the shear layer compared to in smooth flow, as small scale freestream turbulence breaks down cylinder-generated larger scale eddies and weakens them; but does not evidently affect the vortex shedding frequency, or the length of the recirculation region behind the cylinder. This suggests negligible change of drag coefficient compared to in smooth inflow. Moreover, this is because the vortex shedding is dominated by the forced oscillation at the resonance frequency, and the turbulence intensity is small.

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Accepted/In Press date: 12 October 2022
Published date: 16 October 2022
Additional Information: Funding Information: The authors would like to thank EPSRC for the computational time made available on the UK supercomputing facility ARCHER via the UK Turbulence Consortium (EP/L000261/1 for the old grant 2013–2018 and EP/R029326/1 for the new grant 2018–2022). Z.-T.X. is grateful to the EPSRC grant EP/V010514/1 for funding their time contributing to completion of the paper. Publisher Copyright: © 2022 by the authors.
Keywords: integral length scale, oscillating square cylinders, shear layer, turbulence intensity, wake

Identifiers

Local EPrints ID: 471599
URI: http://eprints.soton.ac.uk/id/eprint/471599
ISSN: 2311-5521
PURE UUID: bc540d75-3ceb-4077-b7c9-d891d9a7f044
ORCID for Zheng-Tong Xie: ORCID iD orcid.org/0000-0002-8119-7532

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Date deposited: 14 Nov 2022 18:03
Last modified: 15 Nov 2022 02:38

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Contributors

Author: Yongxin Chen
Author: Kamal Djidjeli
Author: Zheng-Tong Xie ORCID iD

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