RDDES for Strong Shock-Wave/Boundary Layer Interaction

Detached eddy simulation (DES) is a suitable method for the simulation of complex turbulent flows, providing an access to the resolved turbulent scales at relatively low computational cost. The near wall region is solved by (U) RANS whereas the large scale detached region by large eddy simulation (LES). The RANS equations can give significant error when applied to flow involving shock-waves and their interaction with adverse pressure gradient boundary layers. Turbulence models based on eddy viscosity assumption yield very high amplification of the turbulent kinetic energy (TKE) under such non-equilibrium conditions and violate the realizability constraint. The main problem arises in shock-induced separated flows in rocket nozzles which are very sensitive to separation point prediction, and may completely change the flow physics with standard eddy viscosity models. In the present study a new version of DES has been proposed which deals fairly well with such type of flow configurations. Furthermore, emphasis is put on the problems includes (i) modelled stress depletion (MSD) and grid induced separation (ii) realizability issue and (iii) model sensitivity in supersonic separated flow regimes.