In the present work, a computational model based on an Eulerian-Eulerian approach was used for the simulation of the transient two-phase flow in a rectangular partially aerated bubble column. Superficial gas velocities (U-G) ranging from 0.24 to 2.30 cm/s were used throughout both the experiments and the simulations. The calculated results were verified by comparing them with experimental data including measurements of gas hold-up, plume oscillation period (POP) and Sauter mean bubble diameter. The study shows the effect of mesh refinement, time-step and physical model selection, the latter regarding the role of bubble size distribution and non-drag forces, on the computational results. According to the results presented here, the representation of bubble populations using multiple size groups (MUSIG model) instead of a single group improves the prediction of the experimental parameters under study. Additionally, the results obtained after including the virtual mass force term do not differ considerably from those obtained including only the drag force. On the contrary, as a consequence of introducing the lift force term into the model, the gas hold-up is overestimated and a non-symmetric bubble plume oscillation appears, a fact that is not experimentally observed. (C) 2007 Elsevier B.V. All rights reserved.