Zonal Hybrid RANS-LES Simulation of a 1.5-Stage Turbine

Abstract This article introduces a novel method to conduct zonal hybrid RANS-large eddy simulations (LES) of turbomachinery configurations and demonstrates its application to a 1.5-stage turbine. The method extends the classical mixing plane concept to provide bidirectional interface conditions between RANS and LES subdomains. A rotational synthetic turbulence generator is combined with the mixing plane approach at the inlet of LES subdomains. The method features the reconstruction of modeled turbulence quantities at the outlet of a LES subdomain required by a downstream RANS subdomain. The application to the 1.5-stage turbine displays the feasibility of the coupling interfaces to conduct an embedded LES in the confined space of the turbine’s rotor. The flow analysis highlights predictive differences between the embedded LES and a reference pure RANS simulation in terms of secondary flow effects in the rotor subdomain.