A comparative study of 2D and 3D modeling of turbulent flow over a backward-facing step using the GEKO turbulence model

This study presents a numerical investigation of turbulent flow over a backward-facing step using the RANS-GEKO turbulence model implemented in ANSYS Fluent. Simulations were performed in both two-dimensional (2D) and three-dimensional (3D) configurations to assess the influence of flow dimensionality on separation and reattachment characteristics. The distributions of pressure coefficient (Cp) and skin friction coefficient (Cf) were analyzed and compared with experimental data from the NASA Turbulence Modeling Resource. The results demonstrate good agreement with experiments, with the 3D model providing more accurate predictions of the recirculation region and reattachment length. The findings confirm that the GEKO model is an effective and reliable approach for simulating complex separated turbulent flows.