Effects of wall admittance changes on aeroelastic stability of turbomachines

In the present investigation a kind of new lifting surface model has been suggested based on the application of generalized Green's function theory and double Fourier transformation technique, which is suitable for supersonic cascade with subsonic leading-edge locus. The theoretical analysis shows that the change of wall boundary condition not only affects the eigenvalues of the system but also the eigenfunction normalizing factor in comparison with a rigid boundary condition, and it is these variations that affect the flow and acoustic field. On the other hand, through the present numerical simulation the change of wall admittance leads to very remarkable effects on both the lift and moment coefficients, which will determine whether a nonrigid wall has a positive effect on suppressing blade flutter or not. This means that if one aims at suppressing cascade flutter by use of a nonrigid wall one of the best ways is to find soft wall with a controllable acoustic admittance.