Turbulence modeling approaches on unsteady flow structures around a semi-circular cylinder

• Published in: Ocean engineering 2020-03, Vol.200, p.107051, Article 107051
• Main Authors: Yagmur, Sercan, Dogan, Sercan, Aksoy, Muharrem Hilmi, Goktepeli, Ilker
• Format: Article
• Language: English
• Subjects: Bluff body; CFD; Fluid-structure interaction; LES; RANS; Semi-circular cylinder
• ISSN: 0029-8018; 1873-5258
• DOI: 10.1016/j.oceaneng.2020.107051

This paper presents the flow field around a Semi-Circular Cylinder (SCC), a basic geometry for fluid mechanics, obtained numerically by Computational Fluid Dynamics (CFD) at Reynolds number of 3.2 × 104. Time-averaged flow characteristics such as vorticity, velocity fields with streamline patterns, Reynolds stress correlations, Turbulence Kinetic Energy (TKE), pressure and drag coefficients have been examined by using Reynolds-averaged Navier-Stokes (RANS), Detached Eddy Simulation (DES) and Large Eddy Simulations (LES) turbulence models. Several RANS approaches with turbulence modeling including SST k-ω, k-ε and their derivatives were used, while in the LES simulations, the dynamic Smagorinsky subgrid-scale model was employed. The obtained results of the present study have been compared with an experimental study from the open literature. The results of the investigation showed that when numerical findings are compared to experimental ones, the results of LES and DES turbulence models were found to be more consistent than those obtained by using k-ε and SST k-ω models. Time-averaged flow patterns have been found to be considerably symmetric with respect to the axis passing through the end of the curved surface of the SCC. The deviation of LES and DES results, and experimental results was less than 7% in terms of the drag coefficient. [Display omitted] •Flow around a semi-circular cylinder was investigated via CFD using RANS, DES and LES turbulence models.•The instantaneous and time-averaged flow structures were obtained.•CFD results were validated with an experimental study.•The drag coefficients were compared with experimental results.•The closest result to the experimental study was found by the LES turbulence model.