Improved Embedded Approaches

Kurzfassung

In contrast to the non-zonal, DES-like, hybrid approaches, in which a transition from RANS to LES relies upon a natural instability of separated shear layers in massively separated flows, the zonal RANS-LES (actually, RANS – Wall Modelled LES or RANS-WMLES) hybrids imply the presence of a sharp interface between the flow regions treated by RANS and LES. The location of this interface may be arbitrarily specified by the user based on their understanding of the flow physics, available computational resources or the objectives of the simulation, e.g., a need for unsteady flow characteristics. Thus, the embedded approaches are capable of predicting not only massively separated flows but also flows with shallow separation and fully attached flows and in this sense they are more general than the non-zonal ones.