High-Fidelity Simulation of the Interaction Between a Simplified Axial Compressor Cascade and an Ingested Vortex

Abstract

The aim of this research is to analyze the flow generated by the interaction between a simplified linear blade cascade of an industrial aircraft engine demonstrator and an ingested vortex with the aerodynamic characteristics of a ground vortex in real conditions. Due to the lack of experimental and high-fidelity numerical studies in the literature, a representative academic case of this phenomenon with a high-fidelity resolution of turbulence is performed and taken as reference. After the description of the computation setup and the numerical parameters used, the instantaneous topology of this complex flow is discussed, especially the interaction of the compressor cascade with the dynamics of the vortex. The hybrid RANS/LES simulation shows the chopping of the vortex, its destabilization and its dislocation into turbulent structures downstream the blade cascade. Turbulence is finely resolved in the blade wake and in the chopped vortex by the ZDES technique at a moderate computational cost thanks to RANS treatment of attached boundary layers. A decrease of the eddy viscosity injected in the URANS simulation allows a representation of the averaged vortical structures inside the vortex closer to the averaged reference case. Spectral analyses are performed on unsteady velocity signals from probes located inside and outside the vortex chopped by the blades, highlighting more turbulent structures inside the transformed vortex than in the wake of the blades, which are convected downstream in the direction of the Outlet Guide Vane (OGV).