On computations of complex turbulent flow by using nonlinear k-ω 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 into account the anisotropy of the Reynolds stresses, and the effects of extra strain rates which are usually caused by a streamline curvature and the rotation of the flow passages. The governing equations are discretized using a nonstaggered finite-volume formulation employing a bounded higher-order differencing scheme. Five cases of turbulent flows are simulated numerically: fully developed turbulent flows in a channel without rotation, in a curved channel, in a rotating channel, and the flow over a two-dimensional blunt rectangular section. Both flow and heat transfer characteristics were examined for the aforementioned flow passages. The comparisons were made among the present computations using both linear and nonlinear k-omega models, published experimental data, and results obtained by Direct Numerical Simulation (DNS). It was shown that the nonlinear k-omega model generally gives superior results over the existing linear k-omega model by demonstrating better agreement with the data for both flow and heat transfer computations.