Prediction of Turbomachinery Aeroelastic Behavior From a Set of Representative Modes

Abstract

A method is proposed for the determination of the aeroelastic behavior of a system responding to modeshapes which are different from the tuned in vacuo ones, due to mistuning, mode family interaction, or any other source of modeshape perturbation. The method is based on the generation of a data base of unsteady aerodynamic forces arising from the motion of arbitrary modes and uses least square approximations for the prediction of any responding mode. The use of a reduced order technique allows for mistuning analyses and is also applied for the selection of a limited number of arbitrary modes. The application of this method on a transonic compressor blade shows that the method captures the aeroelastic properties well in a wide frequency range. A discussion of the influence of the modeshapes and frequency on the final stability response is also provided.