Stall-Flutter in Cascade : 1st Report, Translatory Vibration of Cascade Blades as Treated by Semi-Actuator Disc Method, Part 1

Abstract

Among theoretical studies about the aerodynamic force acting on vibrating blades in turbomachines, Whitehead's theory is the only one that has ever been undertaken for treating both stalled and unstalled blade vibrations on a unified basis. Unfortunately he made mistakes in comparing the order of magnitude of infinitesimal quantities, and moreover the assumption of the actuator disc cannot be expected to give a stability criterion for the blade flutter, because the assumption itself means that the reduced frequency is always zero, so his theory could give nothing but the erroneous results. Nevertheless, the actuator disc method first applied by him to the vibration problems is very promising. This paper, correcting his mistakes, gives a theoretical method of calculating the aerodynamic force by the "semi-actuator disc" method which is an extension of the actuator disc method.