Modal Analysis of Unsteady Aerodynamic Response of Subsonic Annular Cascade with Steady Loading under Elastic Vibration.

Aerodynamic analysis based on the double linearization theory has been combined with a structural analysis by a finite element method to study the unsteady aerodynamic response of a rotating subsonic annular cascade composed of twisted blades undergoing three-dimensional elastic vibrations with chordwise displacements and flexible deformations. Numerical results are presented to demonstrate the unsteady pressure difference distributions on blade surfaces, aerodynamic works, three-dimensional effects and flutter boundaries for two kinds of cascade blades. In particular, it is found that the second elastic vibration mode can be most unstable for a turbine-type cascade with small camber operating at a subsonic Mach number.