The turbulent flow in a square-duct at a bulk Reynolds number of 10,000 was simulated using the flow simulation methodology and filter-based Reynolds-averaged Navier-Stokes hybrid turbulence models. Simulations were carried out for 3 different grid resolutions to determine how well the hybrid models adapt to changes in the grid resolution. A comparison of instantaneous flow fields, bulk velocities, and profiles of resolved, unresolved, and total turbulence kinetic energy is provided. The hybrid turbulence model that delivered the best results for the square-duct flow was then employed for simulations of the Stanford asymmetric diffuser. The diffuser flow is physically more complex and features a turbulent separation bubble.