Design Criteria for Turbomachinery Periodic Structures to Improve Tolerance to Inflow Distortion and Resonant Oscillatory Flows

The purpose of this paper is to discuss typical problems caused by pressure waves of large amplitude propagating in a circumferential direction in turbomachinery. Opportunities for design control of cascade resonance as a means of protecting turbomachinery from these pressure waves are presented. Some of the critical areas are compressor rear frame diffuser and main combustor instability, afterburner screech, shock wave flutter instability of high-pressure ratio, variable-geometry jet nozzles, compressor stall, compressor stage 1 blade fatigue failures, and labyrinth air seal fatigue failures caused by flexural vibration of the thin walls.