A priori evaluations and least-squares optimizations of turbulence models for fully developed rotating turbulent channel flow

The present study involves a priori tests of pressure-strain and dissipation rate tensor models using data from direct numerical simulations (DNS) of fully developed turbulent channel flow with and without spanwise system rotation. Three different pressure-strain rate models are tested ranging from a simple quasi-linear model to a realizable fourth order model. The evaluations demonstrate the difficulties of developing RANS-models that accurately describe the flow for a wide range of rotation numbers. Furthermore, least-squares based tensor representations of the exact pressure-strain and dissipation rate tensors are derived point-wise in space. The relation obtained for the rapid pressure-strain rate is exact for general 2D mean flows. Hence, the corresponding distribution of the optimized coefficients show the ideal behaviour. The corresponding representations for the slow pressure-strain and dissipation rate tensors are incomplete but still optimal in a least-squares sense. On basis of the least-squares analysis it is argued that the part of the representation that is tensorially linear in the Reynolds stress anisotropy is the most important for these parts. (C) 2007 Elsevier Masson SAS. All rights reserved.