Abstract
In this study, the capabilities of the explicit algebraic stress models used to predict homogeneous and inhomogeneous shear flows are examined. The applications of the models are first focused on the homogeneous flow under shear (homogeneous shear flow) and purely irrotational strains flows (plane strain, axisymmetric contraction and axisymmetric expansion). The ratio of the production to dissipation rate in the explicit algebraic stress model is obtained explicitly. This is found to be important to predict correctly the anisotropy levels of the homogeneous strain flows under purely irrotational strains at elevated strain rates.The asymptotic analysis is also adopted to analyse the model behavior at the state where strain approaches infinity. Comparisons of the predicted results with DNS data and measurements indicate that the model predicts reasonable well the homogeneous shear and axisymmetric contraction cases. The predicted anisotropic level under axisymmetric expansion is too high, and in the plane strain case, the model produces higher level of anisotropy and a wrong sign of the stress anisotropy in the direction without strain.Finally, turbulent recirculating flows within sudden expanding pipes are further simulated with explicit algebraic stress model and anisotropic eddy viscosity model. Both models show a betteer stress-strain interaction, showing a reasonable shear layer development. The anisotropic stress fields are also accurately predicted by the models, though the anisotropic eddy viscosity model of Craft et al. returns marginally better results.