Performances of LES and RANS Models for Simulation of Complex Flows in a Coaxial Jet Mixer

Flow and mixing processes in a classical coaxial jet mixer have been investigated numerically. Calculations have been performed using three Large Eddy Simulation models and three unsteady RANS models. The time averaged mixture fraction and axial velocity, their rms values and energy spectra are compared with LIF and LDA measurements for both j- and r-modes of the jet mixer flow. A special attention is paid to the ability of different models to reproduce unsteady effects. The analysis demonstrates the superiority of the LES method with the dynamic mixed SGS model (DMM) with respect to other RANS and LES models.