Large eddy simulation of flow in LWR fuel bundles.

Advances in computational fluid dynamics (CFD), turbulence modeling, and parallel computing have made feasible the development of codes that can simulate 3-D flows and heat transfer in realistic LWR fuel bundle geometries. Although no single existing RANS (Reynolds averaging of the Navier Stokes equations) turbulence model predicts a sufficiently wide range of flows with accuracy adequate for engineering needs, at this time for most flows the k-{epsilon} models seem to be the best choice. In Ref. 1, it was shown that in LWR fuel-bundle flows the predictions of these models for turbulence intensity are in significant disagreement with experimental measurements. The objective of this work was to assess the predictive power of the constant-coefficient Smagorinsky Large Eddy Simulation (LES) model, the simplest of the LES models, in a typical single-phase LWR fuel-bundle flow