Accurate Prediction of the Wall Shear Stress in Rod Bundles with the Spectral Element Method at High Reynolds Numbers

Wall-bounded flows at high Reynolds number are characterized by high rates of shear at the walls. Resolving the flow near the wall, is critical to correctly reproducing the turbulence. In the present paper, we show that the accurate prediction of spatially varying wall shear stress requires additional near-wall resolution for large eddy simulation. We also demonstrate the advantage of the use of higher order polynomials for such calculations. The difficulties of resolving derivatives in a weak formulation are considered. A large eddy simulation of a channel flow is performed in order to examine these difficulties in a canonical flow. The dependence on resolution and subgrid-scale models is investigated. Results are compared with direct numerical simulation. A large eddy simulation of a single rod in a periodic array at Re=64590 is performed. The results of h-refinement and p-refinement are compared. Wall shear stress and additional results are compared with experimental data. Implications for rod bundle calculations are discussed.