A study of supersonic cascade flutter

Abstract

Supersonic flow past oscillating flat plate cascades with supersonic leading-edge locus is analysed using a linearized method of characteristics valid for arbitrary frequencies and an elementary analytical theory valid only for low frequencies of oscillation. These two methods are extensions of previous work by Teipel and Sauer for the single airfoil in an unbounded supersonic flow to the case of airfoils oscillating in cascade. Included is the determination of pressure distribution and both a two-degree-of -freedom (bending and torsi'on) flutter analysis and a single-degreeof- freedom (torsion) flutter analysis. Numerically determined flutter boundaries are presented for various primary parameters such as, Mach number, solidity, stagger angle, density ratio, structural damping coefficient, and elastic axis position. Also, results are presented for the related problem of supersonic wind tunnel interference (including the effect of tunnel porosity) and airfoil-airfoil interference.