Comparison of numerical results of RSM turbulence models for the problem of asymmetrical plane diffuser

Fundamental processes of turbulent flow separation have long presented a significant challenge for developers of numerical turbulence models. The main difficulty lies in reproducing these processes with a high degree of accuracy, which is largely due to the limited availability of experimental data necessary for model verification. The lack of an extensive experimental database hinders the verification and optimization of computational models of turbulent flow. Studies of the behavior of turbulent flow in an asymmetric flat diffuser were carried out by several independent researchers, among whom we can note the works of Obi et al., as well as Buis. In particular, the experimental data obtained by Buis are widely used as a standard for comparison with the results of numerical simulations. These data allow us to evaluate the accuracy of various turbulence models in describing complex processes of flow separation and recovery. Currently, several types of models based on the second-order closure equations (RSM) have been developed: RSM S-omega, RSM BLS and RSM Linear L-S. Each of these models has its own characteristics, which allows us to evaluate their efficiency under various flow conditions. This paper examines the ability of RSM models to accurately determine key turbulent flow characteristics such as flow detachment and reattachment locations. Accurately identifying these zones is critical to modeling turbulent flow in a flat asymmetric diffuser, as it affects pressure, flow velocity, and flow stability.