The use of variable area ducts was found to magnify the secondary fluctuations in mass flow rate prediction. Overall, Model IV was found to give the best compromise of results in this study. Though the present models managed to predict unsteady turbine flow performance to varying degrees of accuracy, additional experimental data would be required to further validate the modeling approach (i.e., instantaneous pressure along the turbine volute and mass flow rate in the turbine outer limb). Besides, the present models are unable to predict the efficiency of the turbine. Future work will extend the numerical models for turbine torque and efficiency calculations. This is vital to a complete validation of the numerical model against measured turbine efficiency since this determines energy flow to the compressor and thus the intake air delivery to the engine. Nonetheless, the findings of this study help to understand the appropriateness of some assumptions in full admission one-dimensional twin entry turbine modeling under pulsating flow.