Application of a new methodology for simulations of complex turbulent flows

A new "Flow Simulation Methodology" (FSM) is presented, which is based on employing a new type of turbulent stress model for time dependent turbulent flow computations in the general form of Large Eddy Simulations (LES). Therefore, FSM is similar to LES in the sense that the large scales are computed and the small scales are modeled. The main difference, however, between our FSM and traditional LES is that the subgrid-scale stress model of LES is replaced by the product of a contribution function and a state-of-the-art Reynolds stress model. The contribution function is designed such that, when FSM is integrated into the Navier-Stokes code, simulations approach an unsteady RANS calculation when the grid resolution is decreased (or the Reynolds number is increased). Conversely, simulations approach a DNS when grid resolution is increased (or the Reynolds number is decreased). With the FSM, it should be possible to simulate complex turbulent boundary layer flows to a greater degree of accuracy than with traditional RANS or LES methods. The new model was implemented and tested for turbulent flat plate boundary layer flows, both with and without separation. The results have shown many distinct features, indicating that the new methodology is very promising.