Effects of wall admittance changes on aeroelastic stability of turbomachines

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