Towards the efficient turbulence closure for mixing phenomena in the core outlet of a nuclear reactor

The present study provides a quantitative assessment of different approaches for turbulence modeling (RANS, URANS and LES) in terms of accuracy and computational costs. The accuracy is evaluated by direct comparison of the numerical results to the experimental data and the costs are assessed from the processor time spent for simulation. The results show that the average cost of unsteady simulations is higher than RANS almost by two orders of magnitude. Although the increase in the accuracy is not very big, the RANS simulations seem to be more efficient for the considered flow.