    The objective of this research is to study the formation of a separation bubble over a 2D half-body by Reynolds Averaged Navier-Stokes (RANS) simulation. This numerical simulation technique uses a reduced computational data and has been adopted for most practical engineering problems, since the design of such applications relies on the steady state flow and average velocity field. The main purpose is to analyze the flow dynamics of the recirculation bubble for dimensionless parameter η = R/H (ratio of rounded radius and body height). One case is investigated, corresponding to η = 0.25. The Reynolds number, based on the free-stream velocity U∞ and the height of the obstacle H, is equal to Re = 2000. The solutions obtained through the Reynolds Averaged Navier-Stokes (RANS) equations for the two-dimensional steady state flow uses the Spalart-Allmaras and SST (Shear Stress Transport) κ-ω models. These RANS models assume isotropic modeling of the Reynolds tensor. The results are compared with computational data.