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ARTICLE

Two-Dimensional Numerical Study on the Flow Past Two Staggered Cylinders in a Channel

Zenan Lai, Deming Nie^*

College of Metrology Measurement and instrument, China Jiliang University, Hangzhou, 310018, China

* Corresponding Author: Deming Nie. Email:

(This article belongs to the Special Issue: Recent Advances in Computational Fluid Dynamics)

Fluid Dynamics & Materials Processing 2025, 21(9), 2131-2148. https://doi.org/10.32604/fdmp.2025.068091

Received 21 May 2025; Accepted 01 August 2025; Issue published 30 September 2025

Abstract

The lattice Boltzmann method (LBM) is employed to simulate flow around two staggered cylinders within a confined channel. The numerical model is validated against existing experimental data by comparing drag coefficients and Strouhal numbers in the single-cylinder configuration. The study systematically investigates the influence of vertical () and horizontal () spacing between the cylinders, as well as the Reynolds number ( = 0.1–160), on the hydrodynamic forces, streamline patterns, and vortex dynamics. Results indicate that reducing the horizontal spacing  suppresses flow separation behind the upstream cylinder, while either excessively small or large vertical spacing  diminishes separation in the downstream cylinder. The onset of periodic vortex shedding is delayed due to inter-cylinder interactions, with the critical Reynolds number increasing to  = 71–112, significantly higher than that of a single-cylinder case ( ≈ 69). During the vortex shedding regime, the downstream cylinder exhibits a greater lift force fluctuation compared to the upstream cylinder. At  = 160, the root-mean-square lift coefficient () ranges from approximately 0.17 to 0.56 for the downstream cylinder, and from 0.018 to 0.4 for the upstream one. The shedding frequency, characterized by the Strouhal number (), increases with Reynolds number, reaching  = 0.12–0.18 at  = 160. Variations in  and  significantly influence , with a decrease in  or an increase in  lowering the shedding frequency—this effect is more pronounced in the horizontal direction.

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Keywords

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