NONLINEAR 2ND-MOMENT CLOSURE CONSISTENT WITH SHEAR AND STRAIN FLOWS

A pressure-strain correlation closure consisting of a polynomial tenso r ansatz, most general in the Reynolds-stress anisotropy and linear in the mean velocity gradient, is presented, Following Johansson and Hal lback (Johansson, A. V., and Hallback, M., ''Modelling of Rapid Pressu re-Strain in Reynolds-Stress Closures,'' Journal of Fluid Mechanics, V ol. 269, 1994, pp. 143-168), the coefficients of the ansatz are expand ed in series in terms of the anisotropy tensor invariants to ensure re alizability. In this work, the free model constants are calibrated to account for relaxation flow experiments, equilibrium state characteris tics of nonrotating and rotating homogeneous shear hows, The model is combined with the standard dissipation rate equation and a simple turb ulent transport model, The new closure is compared to the successful a nd simpler closure of Speziale et al. (Speziale, C. G., Sarkar, S., an d Gatski, T. B., ''Modelling the Pressure-Strain Correlation of Turbul ence: An Invariant Dynamical Systems Approach,'' Journal of Fluid Mech anics, Vol. 227, 1991, pp. 245-272), who first introduced the calibrat ion arguments used herein, It is superior to the simpler model in pred icting relaxation and strain flows and also ensures realizability, The good prediction of all investigated homogeneous turbulent flows and a self-preserving round jet emphasizes the wide range of applications f or the new model.