Numerical workflow for scale-resolving computations of space launcher afterbody flows with and without jets

Abstract

Scale resolving numerical methods are necessary to accurately predict the afterbody flows of space launchers. Numerical workflows built for such computations have to be designed in order to obtain a minimal numerical dissipation to resolve fine turbulent structures, a sufficient robustness to capture eventual shock waves and both a reasonable computational cost and an acceptable user workload enabling comparative design studies. This article presents the development of a hybrid numerical framework based on Ducros’s sensor and designed to switch from a low-dissipation formulation in presence of vortical structures to a robust formulation around high gradients. This hybrid workflow is used with ZDES, including its latest automatic mode (ZDES mode 2 (2020)), to simulate a transonic space launcher afterbody experiment with and without a cold air propulsive jet [1,2]. The salient physical properties of the base flow are investigated and the evaluation of computed results follows the extended nomenclature for validation of simulation techniques [3] from level 0 to 5. The framework is thus validated for instantaneous and mean flow visualizations, base and extension mean pressure coefficient distribution, pressure fluctuation levels, one-point and two-point spectral analyses. Such an efficient automatic RANS/LES strategy could be well suited to study realistic launcher afterbody geometries with propulsive jet(s).