Experimental Investigation and Theoretical Prediction of Flutter Behaviour of a Plane Cascade in Low Speed Flow.

Kurzfassung

The Institute of Aeroelasticity operates a test facility which enables the aeroelastic investigations of plane cascades in low- speed flow. The test stand serves as a pilot facility to develop tools for analogous investigations in transonic flow. Eleven blades are elastically suspended in a windtunnel with a 1x0.2 square meter cross section. This paper describes the experimental method of determining the flutter boundary by extrapolation of the results measured in subcritical flow. A 2D theoretical model of the 11 blades including the windtunnel walls permits the computation of unsteady pressures, forces and moments in close relation to the experiment. The prediction of flutter is compared with experimental results. In the present investigation, the motion of the blades is constrained to pitch around mid-chord. The vibrating blades are mechanically uncoupled. Any interaction between the blades is effected by the air stream, leading to a sensitive dependence on the aerodynamic forces.