Nonlinear aerodynamic damping in a highly loaded vibrating compressor cascade

Abstract

A numerical aeroelastic study of a 2D linear compressor cascade based on the non-rotating annular compressor cascade with a NACA3506 profile was performed using a one-way coupled technique (prescribed-motion approach). Subsonic and transonic flow conditions with strong shocks in the blade passage were imposed. Using a nonlinear harmonic balance solver, unsteady simulations were performed by enforcing one blade oscillation motion. For each blade structural mode, the blade deflection amplitude was varied and its influence on the blade aerodynamic response was determined in terms of aerodynamic damping. The blade modes investigated consisted of one pitching and two heaving oscillation motion. In transonic flows and for the three structural modes investigated, the cascade shows nonlinear aerodynamic responses depending on the vibration amplitude. The results presented in this work show that nonlinear frequency domain methods are able to capture the blade nonlinear aeroelastic behavior coming from amplitude-dependent aerodynamic responses.