The stirred tank reactor is one of the most commonly used devices in industry for achieving mixing and
reaction. Here we report on results obtained from the large eddy simulations of flow inside the tank performed
using a spectral multi-domain technique. The computations were driven by specifying the impeller-induced
flow at the blade tip radius. Stereoscopic PIV measurements (Hill et al.^ (1)) along with the theoretical model of
the impeller-induced flow (Yoon et al.^ (2)) were used in defining the impeller-induced flow as superposition of
circumferential, jet and tip vortex pair components. The multi-planes stereoscopic PIV measurements give the
information of volumetric velocity, which provide the three-dimensional spatial structures of flow driven by a
six bladed Rushton turbine in an unbaffled tank. We perform the stereoscopic PIV measurements for the same
geometry and operation conditions to evaluate the reliability of the numerical predictions. At Rem=4300
considered here, the flow in the interior of the tank naturally evolves to a time-dependent turbulent state. The
improved impeller-induced inflow allowed for the development of tip vortex pairs in the interior of tank. The
time-averaged location of the vortex backbone compares well with measurements. The radial profile of timeaveraged
radial velocity along the mid-plane at different circumferential locations provides a very good
sensitive measure for evaluating the accuracy of the simulation. Here, we focus on the study of effects of the
simplest time averaged turbulent characteristics on mean flow field.