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Aerodynamics and Wake Flow Characteristics of a Four-Cylinder Cluster

Nguyen, C; Inam, S; Lasagna, D; Xie, ZT

Aerodynamics and Wake Flow Characteristics of a Four-Cylinder Cluster Thumbnail


S Inam

D Lasagna

ZT Xie


The aerodynamic behaviour and wake flow of a cluster of two-dimensional sharp-edged bluff bodies exhibits extremely complex unsteady phenomena in both near and far fields. Due to the high cost of wind-tunnel experiments and numerical simulations, a complete understanding of wake flows and a description of their characteristics are lacking. This paper presents large-eddy simulations (LES) in different flow/wind directions for a cluster of 2×2
aligned square cylinders, at a separation distance in streamwise and cross-wind directions equal to cylinder side length, and at Reynolds number Re=22,000
based on the single cylinder side length D. The case at 0∘
incidence shows an evident channel-type flow in the along-wind street/gap, and at its exit an irregularly pulsing jet with an intense shedding of large vortices. The wavelet analyses of the side force/lift coefficient and instantaneous velocities in the wake show that the characteristic length and time scales of the large vortical structures in the far-field wake are close to the cluster size 2D; this is the so called ‘cluster effect’. The cluster effect increases monotonically as the flow incidence angle increases. At a large incidence angle in the near-field wake, the cylinder-scale flow structures are much weaker compared to the cluster-scale structures. At the incidence angle of 45∘
, the overall wake flow and the aerodynamic characteristics are well scaled by the scale approximately equal to 2D. Nevertheless, the interaction between cylinders significantly affects the aerodynamics performance of the individual cylinders. The drag and lift coefficients of the individual cylinders differ substantially from each other in the cluster, and are significantly different from observations on a single isolated cylinder too.


Nguyen, C., Inam, S., Lasagna, D., & Xie, Z. (2023). Aerodynamics and Wake Flow Characteristics of a Four-Cylinder Cluster. Flow, Turbulence and Combustion, 110,

Journal Article Type Article
Acceptance Date Apr 12, 2023
Publication Date Apr 26, 2023
Deposit Date Jun 9, 2023
Publicly Available Date Jun 9, 2023
Journal Flow, Turbulence and Combustion
Print ISSN 1386-6184
Publisher Springer Verlag
Peer Reviewed Peer Reviewed
Volume 110


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