Accurate turbulence modeling remains a critical problem in the prediction capability of computational fluid dynamics. One particular area lacking accurate simulations is separated turbulent flows. In this paper, the recently developed one - equation Rahman-Agarwal-Siikonen (RAS) turbulence model is used to simulate the flow of several canonical turbulent flow cases. The commercially available software ANSYS Fluent and the open source software OpenFOAM are used for the flow field calculations. It is shown that the RAS model improves the accuracy of flow simulations compared to the commonly used one - equation Spalart-Allmaras (SA) and two-equation SST k-ω turbulence models.