The objective of the present work is to evaluate the steady and unsteady Reynolds-averaged Navier-Stokes (RANS) approach turbulence model for separated flow applications. A υ²- f model based on the standard k - ω model is employed and referred to as the k - ω - υ²- f model. This model is validated by flow around two- and three-dimensional bluff bodies. The selected configurations are a single square cylinder, tandem square cylinders and cube. The flow predictions are discussed and compared with available experimental and numerical data. For these cases, none of the previously published numerical predictions obtained by steady-state RANS produced a good match with experimental data. Because these flow cases are inherently unsteady at high Reynolds numbers, unsteady RANS computations should be employed. It is found that the results obtained with this mode are in agreement with the available experimental and numerical data.