Based on conventional turbulent jet theory and the general theoretical framework of scalar dispersion in turbulent shear flows, a novel formulation of the radial impeller's jet in stirred tanks is introduced. Whereas previous studies considered the impeller's jet as developed, it is now comprised of two separate spatial regions along the radial axis: the zone of flow establishment (ZFE) and the zone of established flow (ZEF). This formulation is accompanied with semi-analytical expressions for the prediction of turbulent key parameters including the random part of k and epsilon in the ZFE. The new theoretical framework is validated both with laser Doppler anemometry measurements and with 3-D numerical simulations using the standard k-epsilon turbulent model. (C) 2015 American Institute of Chemical Engineers