Numerical Study on Stall Flutter of A Compressor Cascade (1st Report, Numerical Method and Numerical Example)

摘要

Stall flutter of a compressor cascade is studied by numerical analysis of the unsteady separated flow around the blades oscillating in a torsional mode. A numerical method in developed for the present study, in which used are a discrete vortex modeling to calculate the convection and the diffusion of the vorticity in the separated flow and a grid system deforming together with the blade oscillation. The present method is applied to the compressor cascade working at such an inlet flow angle where the rotating stall is also liable to occur. The numerical result shows that the shedding of strong vortices from the leading edge of the blades has dominant influences both on the flow behavior and on the flutter excitation of the oscillating blades, and that the occurrence of the stall flutter is closely connected with the propagation of the rotating stall.