Comparison of numerical results of linear and nonlinear turbulence models based on the rans approach

\nThis paper considers one of the urgent problems of modern physics — numerical solution of turbulent flows, which play a key role in various fields of science and technology, including aerodynamics, hydrodynamics and heat transfer processes. The main attention is paid to comparison of two turbulence models: linear model SST (Shear Stress Transport) and nonlinear model RSM (Reynolds Stress Model). Both approaches are widely used for modeling turbulent flows, but their efficiency and accuracy may vary depending on the nature of the flow. To compare these models, the problem of two-dimensional (2D) flow in a sharply expanding channel taken from the NASA database was chosen. This problem is a classic example of complex turbulent flow, which makes it ideal for testing various models. Sharp expansion of the channel leads to complex effects, such as formation of recirculation zones and intense shear stresses, which creates additional difficulties for numerical modeling. The purpose of this study is to assess how accurately each of the models describes complex processes in turbulent flows and to identify their strengths and weaknesses. The work included calculations based on the RANS approach (Reynolds-Averaged Navier-Stokes), which is widely used to model turbulence by averaging the Navier-Stokes equations over time. The results of numerical calculations for both models were compared with experimental data, which allowed an objective assessment of their accuracy.\n