Active Control of Cascade Flutter by Means of Sound Waves from Duct Wall Sources

Abstract

A theoretical analysis of the cascade flutter suppression using active acoustic excitations is presented. A model considered herein is a three-dimensional linear cascade of flat plates oscillating in a subsonic flow between parallel walls. One of the walls is partially made of actuator surface like a loudspeaker which generates sound waves with the same frequency as that of the blade oscillation. The unsteady aerodynamic work on blades due to oscillation and interaction with the acoustic disturbances generated from the actuator surface is calculated. Dependence of the aerodynamic work on the location, width, vibration modes of the actuator surface and the phase difference between the cascade and actuator surface oscillations are investigated. Numerical results show the optimum conditions of the actuator surface oscillation for effective flutter suppression.