Flutter analysis of a tuned rotor with rigid and flexible disks

Abstract

The flutter behavior of a simple tuned rotor with a rigid and a flexible disk is reviewed. In Part A, the rotor assembly is assumed to consist of a rigid disk with N uniform flexible blades attached around the circumference, so that the blades are coupled only by aerodynamic forces. Both traveling wave and standing wave flutter analyses are conducted, and are shown to be equivalent. The relations between traveling and standing wave air forces are described in detail. The standing wave analysis is shown to be more versatile for some applications than the simpler traveling wave analysis. Applications are made to pure bending flutter and pure torsion flutter of the rotor assembly. Comments are made on combined bending-torsion flutter. In Part B, the rotor disk is assumed flexible and shrouds may be present. The blades are here coupled structurally as well as aerodynamically. The corresponding vibration and flutter behavior is examined.