Flutter Analysis of Tandem Cascades Based on a Fluid–Structure Coupling Method

Abstract

The hypothesis of a conventional traveling wave model cannot cover the aerodynamic coupling effect of tandem blade cascades, while the aerodynamic interference between the front and rear blades of the cascade has a remarkable effect not only on the pressurized capacity but also the flutter characteristics. In order to investigate the flutter characteristics of the tandem cascade aeroelastic system, a fluid-structure coupling aeroelastic method and a system identification technique are used to establish a reduced order model (ROM). We analyzed the stability and vibration modes of the system through eigenvalues provided by the ROM. By this method, we can not only get the Inter Blade Phase Angle (IBPA) between blades in the same row, but also, at the same time, the vibration phase relationship between the front and rear tandem blades. Results showed that the stability would be lost when the natural frequencies of front and rear cascades were close to each other. Besides, the fluid-structure coupling effect is more obvious in the case of low mass ratio.