Numerical Analysis of Oscillating Blade in Linear Cascade at Transonic Flow

Abstract This paper explores the numerical simulation of stall flutter in transonic compressor blades. The primary objective is to characterize the flutter patterns observed in oscillating blades impacting stationary blades in a linear cascade arrangement. The study focuses on the STC-5 airfoil configuration, utilizing a cascade assembly with five blades arranged in a linear manner. The oscillation amplitude is set at 2 degrees for the blades adjacent to the center blade (0 degrees) Both steady-state simulations and time-dependent analyses, considering three incidence angles and varying reduced frequencies and IBPA’s. The study underscores the significant role of surface pressure fluctuations induced by shock oscillation in determining unsteady aerodynamic forces affecting blade stability. These fluctuations primarily resulted from the movement of the shock impingement point on the blade surface. It reveals that the oscillation of the separated region, resulting from shock-boundary layer interaction, contributes to additional pressure fluctuations along the blade surface. Both shock oscillation and the movement of the separated region are identified as critical factors influencing unsteady aerodynamic behavior and vibration characteristics in the transonic compressor cascade.