Mirror fluid method [Yang and Mao, Phys. Rev. 2005; E 71:036704] combined with local grid refinement is proposed to deal with the numerical simulation of turbulent flow in a pitched-blade turbine stirred tank. By such a novel method, the domain occupied by the impeller is assigned suitable flow parameters explicitly by the mirror relation, so that the correct shear and normal forces on the fluid side of an interface segment is eventually guaranteed. Satisfactory agreement between our predictions and the reported experimental data is achieved both in single-phase baffled or unbaffled stirred tanks and solidliquid two-phase systems. (c) 2012 Canadian Society for Chemical Engineering