A NEW VARIANT OF THE DYNAMIC HYBRID RANS-LES MODEL FOR COMPLEX TURBULENT FLOWS

This study proposes a new variant of the Dynamic Hybrid RANS-LES (DHRL) model. Since the baseline DHRL model uses the ratio of resolved to modeled turbulent stress in RANS-to-LES blending, it was observed that for some types offlows the DHRL model remained in RANS mode despite the presence of appreciable levels of LES fluctuations. A new statistical variable is introduced in this study and implemented into a modified blending function to facilitate model transition from RANS to LES based on the presence of appreciable levels of resolved turbulence. Numerical simulations are carried out using the density-based finite-volume solver Loci-CHEM for canonical test cases such as fully developed channel flow, flow over a backward facing step, and flow over a three-dimensional axisymmetric hill. A comprehensive analysis of results indicate that the new model successfully addresses some of the shortcomings of the baseline DHRL model and it is concluded that new DHRL model variant is a useful alternative to traditional HRL models.