Hybrid LES — RANS of Complex Geometry Jets

Abstract

Large eddy simulation (LES) type studies are made of a realistic geometry coaxial nozzle with a pylon. For the LES, since the solver being used tends towards having dissipative qualities, the subgrid scale (SGS) model is omitted, giving Numerical LES (NLES). To overcome near wall streak resolution problems a near wall RANS (Reynolds averaged Navier Stokes) model is used giving a hybrid NLES-RANS approach. The pylon is shown to influence the flow development, having a significant impact on peak turbulence levels and spreading rates. The results show that real geometry effects are influential and should be taken into account when moving towards real engine simulations. If their effects are ignored then, based on the studies here, key turbulence parameters will have significant error.