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

Abstract

The Institute of Aeroelasticity operates a test facility which enables 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 wind tunnel with a 1 x 0.2 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 two-dimensional theoretical model of the 11 blades, including the wind tunnel 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 affected by the air stream, leading to a sensitive dependence on the aerodynamic forces.