Hybrid RANS/LES Simulation of a Supersonic Coaxial He/Air Jet Experiment at Various Turbulent Lewis Numbers

In this article, the unstructured, high order finite-volume CFD solver FLUSEPA, developed by Airbus Safran Launchers, is used to simulate a supersonic coaxial Helium/Air mixing experiment. The aim is to assess the ability of the code to accurately represent mixing in compressible flows and to create a reference case in order to test a future hybrid RANS/LES (HRL) model with variable turbulent Prandtl and Schmidt numbers. Both RANS and HRL simulations are performed and the impact of Lewis number on the results is studied. Fine and coarse meshes are used to see the influence of spatial resolution on modeled and resolved scales. General good agreement is obtained for both RANS and HRL simulations. Predictably, the choice of Lewis numbers has almost no impact on the time-averaged fields of the fine HRL simulation. Its role is more significant on the coarse mesh and the steady RANS simulations.