Modes identification and interactions in a rotor/stator academic cavity

Abstract

Hydrodynamics instabilities in rotating stator/rotor cavity flows are of first interest for aerospace companies. Indeed, those self sustained flow waves can be at the origin of a resonating loop which involves the structure resulting in the potential destruction of turbomachinery parts. This paper aims at giving a deeper understanding on the source of the flow oscillations by investigating a rotating cavity flow by use of a global stability analysis in parallel to a Large Eddy Simulation (LES). In particular and for flows with multiple frequencies, mode dominance and interactions can be difficult to address with linear analyses. To better apprehend such equilibrium, a numerical tool named Dynamical Mode Tracking and control (DMTC) is proposed here and tested on the basis of LES. In the case of the stator/rotor cavity, without control, i.e, DMT enables to validate the source of the different modes in agreement with previous studies and linear stability. Finally by controlling the modes one by one with DMTC, interactions between the modes and mode dominance is evidenced.