The flow field generated by the pitched-blade turbine in both laminar and turbulent operation has been investigated using laser Doppler velocimetry (LDV) and digital particle image velocimetry (DPIV) experimental techniques. This data has been used to critically evaluate the performance of computational fluid mixing (CFM) tools. It has been found that current CFM software can accurately predict the laminar flow behaviour of the pitched-blade impeller if the proper velocity boundary conditions are provided around the entire periphery of the impeller. In turbulent operation, CFM simulations predict some of the features of the flow field, but dramatically underpredict the total energy dissipation rate in the vessel. They are not currently capable of describing the large-scale instabilities in the flow detected by DPIV.