On computations of complex turbulent flow by using nonlinear k-omega model

This article presents the performance of a new nonlinear k-omega model for computations of turbulent flows and heat transfer in several different flow types. This model was developed by incorporating cubic terms that take int o account the anisotropy of the Reynolds stresses, and the effects of extra strain rates which are usually caused by a streamline curvature and the ro tation of the flow passages. The governing equations are discretized using a nonstaggered finite-volume formulation employing a bounded higher-order d ifferencing scheme. Five cases of turbulent flows are simulated numerically : fully developed turbulent flows in a channel without rotation, in a curve d channel, in a rotating channel, and the flow over a two-dimensional blunt rectangular section. Both flow and heat transfer characteristics were exam ined for the aforementioned flow passages. The comparisons were made among the present computations using both linear and nonlinear k-omega models, pu blished experimental data, and results obtained by Direct Numerical Simulat ion (DNS). It was shown that the nonlinear k-omega model generally gives su perior results over the existing linear k-omega model by demonstrating bett er agreement with the data for both flow and heat transfer computations.