The Flexure-Torsion Flutter of Aerofoils in Cascade : 1st Report, Computation and Experiment of Unsteady Aerodynamic Derivatives

Abstract

Theoretical and experimental investigation ofthe flexure-torsion flutter of aerofoils in cascadeare presented. In this first report are shown a computational method and computed results of unsteady lift, drag and moment acting on the vibrating aerofoils in cascade, and some experimental results of these unsteady aerodynamic forces and moment. In computation are included the effects of stagger angle, solidity, attack angle (or steady circulation), inter-blade phase angle of vibration and camber of blade (or distribution of steady circulation). Each aerofoil constituting the cascade is considered to have two degrees of freedom of translational vibration (not necessarily normal to blade chord) and torsional vibration about elastic axis. Agreements between computational and experimental results are satisfactory. The effects of cascade parameters on critical flutter speed of binary flutter analyzed using the aerodynamic derivatives developed in this 1st report are shown in the 2nd report.