Yacine Kahil, Abdelkrim Benlefki, Zakaria Rahmani, Djilali Zerrouki, Tayeb Yahiaoui

Abstract: A numerical study was performed to investigate the behavior of an incompressible turbulent flow around four cylinders in a square configuration at a Reynolds number of Re = 3000. The study is performed in order to explain the flow dynamics in tube bundles. Using the Reynolds-Averaged Navier-Stokes (RANS) approach with the k-ω SST turbulence model, the computations were performed using the open source and free software Code_Saturne. Two configurations are analyzed: in-line (α = 0°) and staggered (α = 45°), both with a spacing ratio of P/D = 1.5. The results of the first configuration were validated by comparison with the available experimental and numerical data. The bistability phenomenon was shown based on the different fields of velocity in the in-inline configuration. The analysis of the results of the staggered configurations led to the conclusion that the effect of new configurations on the flow dynamics is well demonstrated by an observation of a jet flow which is distinct from the regular gap flow, characterized by a narrow width and high velocity. Altering the wake shape can cause significant variations in the magnitude and direction of the jet flow, resulting in potential structural vibrations that must be considered in practical engineering applications.

Keywords: CFD, Code_Saturne, turbulent flow, tube bundle, bistability.

Date Published: December 12, 2025
DOI: 10.11159/jffhmt.2025.044

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