Cascade Wind Tunnel Experiment of Stall Flutter.

Abstract

Stall flutter of a compressor cascade is studied by experiment using a wind tunnel with a linear cascade of blades oscillating in a torsional mode. The time varying pressure distribution on the blade surface and the unsteady velocity fluctuation in the blade passages are measured with pressure transducers and hot wire velocimeters. The experimental result shows that the synchronization and the entrainment occur between the blade oscillation and the rotating stall, and that these phenomena have dominant influence both on the unsteady flow behavior and on the flutter excitation of the oscillating blades. The experimental result agrees very well in general with the numerical result performed in advance using a discrete vortex modeling, particularly concerning the relationship between the occurrence of the stall flutter and the propagation of the rotating stall.