Invaluable research efforts have been made to develop a standard turbulence model. However, researchers have failed to uncover the pitfalls being presented thus far. In this study, we have dealt with a two-dimensional flow, viscous and incompressible, around the subsonic profile S809 in a steady state, at Reynold’s number of 1 million, from various angles of attack. Regarding the field’s topological study, we have chosen a structured C-type mesh. The element shape is quadri-angular, and the resolution method is pressure-based. In the first part, a comparison for calculating the aerodynamic performance has been carried out between conventional RANS models (Spalart Almaras, K − ε Realizable model, k − ω (SST) model) and the GEKO (Generalized K − Omega) model in the light of varying the separation of coefficient Csep. According to the results obtained, GEKO models are considered the most effective for predicting drag and lift coefficients. The second part is devoted to highlighting the recently developed GEKO model, which has demonstrated its ability to accurately predict the wake phenomenon and the onset of separation. The GEKO model offered a flexible model that could be adapted to different flow cases without impacting the essential calibration.