Uncertainty-Quantified Grid-Convergence Analysis of RANS Turbulence Models for 2-D Incompressible Backward-Facing Step Flow in OpenFOAM

Authors

DOI:

https://doi.org/10.26877/asset.v8i1.2390

Keywords:

Backward‑Facing Step, RANS Turbulence Models, Grid Convergence Index (GCI), Uncertainty Quantification, OpenFOAM Simulation

Abstract

A concise evaluation of Reynolds-Averaged Navier–Stokes (RANS) turbulence modeling for two-dimensional, incompressible, steady backward-facing step (BFS) flow at Re = 1000–3000 was conducted using OpenFOAM’s SimpleFoam solver with the standard k–ε model. A tri-level mesh enhancement (coarse, medium and fine) was implemented, and ambiguity was measured utilizing the Convergence Ratio (CR) and Grid Convergence Index (GCI). The fine grid (CR = 0.54; GCI = 0.0059%) was the only configuration exhibiting monotonic convergence, ensuring valid GCI estimation. Results showed reattachment length increasing from 0.11 m to 0.12 m, with stronger vortical structures and steeper shear gradients at higher Re. This study uniquely integrates RANS model validation with grid-uncertainty quantification, providing guidance for mesh optimization and reliable turbulence modeling in BFS simulations.

Author Biographies

  • Mickael Ruben Kaiway, Universitas Cenderawasih

    Department of Mechanical Engineering, Cenderawasih University, Jayapura City, Papua Province, 99351, Indonesia

  • Joni, Universitas Cenderawasih

    Renewable Energy Engineering, Graduate School of Cenderawasih University, Jayapura City, Papua Province, 99351, Indonesia

  • Agustinus Giai, Universitas Cenderawasih

    Department of Mechanical Engineering, Cenderawasih University, Jayapura City, Papua Province, 99351, Indonesia

  • Samuel Parlindungan Siregar, Universitas Cenderawasih

    Department of Mechanical Engineering, Cenderawasih University, Jayapura City, Papua Province, 99351, Indonesia

  • Enos Tambing, Universitas Cenderawasih

    Department of Mechanical Engineering, Cenderawasih University, Jayapura City, Papua Province, 99351, Indonesia

  • Obia Pius, Kyambogo University

    Department of Physics, Kyambogo University, Kyambogo, PO Box 1, Uganda

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Published

2025-12-23

Issue

Vol. 8 No. 1 (2026): November - January

Section

Articles