On the coupling of a zonal body-fitted/immersed boundary method with ZDES: Application to the interactions on a realistic space launcher afterbody flow.

Highlights • Generalization of the 2014 version of the ZIBC combining RANS/LES and the IB method. • Extended presentation of the Zonal Immersed Boundary Conditions approach. • First RANS/LES and IBC application to a full space launcher at high Reynolds number. • ZDES/IBC is highly validated for both the statistical field and the spectral content. Abstract One of the next foreseen challenges in CFD consists in the capability to simulate quantitatively the spectral content of the turbulent flow around realistic geometries. In this context, the present work focuses on a new methodology named ZIBC standing for Zonal Immersed Boundary Conditions enabling to account for complex configurations at high Reynolds numbers. The numerical strategy allowing the coupling between a turbulence modeling method (e.g. RANS, URANS, ZDES, LES or DNS) and IBC (Immersed Boundary Conditions) is detailed. In this paper, the modeling method retained is the Zonal Detached Eddy Simulation (ZDES) which has reached a high level of maturity on turbulent separated flow simulations. This methodology is applied to a full space launcher configuration to assess its capability to return the interactions between the technological details, modeled with IBC, and the simplified afterbody, modeled with a body-fitted (BF) approach consisting in classical no-slip boundary conditions, in the turbulent flow field surrounding the main stage of the space launcher afterbody. The proposed method is thoroughly assessed on a realistic geometry of the European Ariane 5 launcher and the ZIBC simulation is successfully compared with the available experiments. [ABSTRACT FROM AUTHOR]