A Liutex-Based Subgrid Stress Model in Periodic Hills

Turbulence problems are very sophisticated, the study of vortex is one of the keys to understand and model it. In large eddy simulation, the researches on small-scale eddies, which also have an impact on large-scale vortices or the resolved flow fields, are by modeling subgrid stress model. Although turbulence is mixed with large and small eddies, it is also the main cause of fluctuations of turbulent physical quantities. However, vortex identification methods are rarely used in these models. In this study, we develop a subgrid stress model based on Liutex and apply it to periodic hills. We change the parameters of the periodic hills and compare the difference with the traditional model. The results show that the new model is of great significance for the analysis of this type of model. Prior to this, Ding had applied it into decaying homogeneous isotropic turbulence and turbulent channel flow, and identified some positive results. In the future another promising finding was that we can take advantage of this Liutex-based subgrid model to do more in-depth research to discover more features of periodic hills as well as apply it to more models. In this paper, in Sect. 1 we introduced what large eddy simulation(LES) is, especially the subgrid models in large eddy simulation and the two commonly used subgrid models(Smagorinsky and WALE). In Sect. 2, we reviewed the development of vortex identification methods, introduced the first and second generation vortex identification methods, and introduced the third generation vortex identification method based on Liutex. Based on the above, we naturally combined Liutex with subgrid models to establish a subgrid model based on Liutex. In Sect. 3, we will apply the Liutex based subgrid model to the periodic hills and compare it with two commonly used traditional subgrid models that we have previously learned.