Turbulence-induced disturbances and their evolution to stall onset in a compressor cascade using large eddy simulation

This study investigates the turbulence-induced disturbances and stall precursor triggering mechanism in NACA65-18(10) cascade based on large eddy simulations. The results indicate that the disturbances exist under various operating conditions along the performance curve. The shear layer is the physical structure responsible for the generation, propagation, and dissipation of disturbances. When operating near stall, the separation on the suction surface intensifies, and strong unsteady backflow occurs at the trailing edge of the passage. Under the influence of inlet disturbances, unsteady behaviors between passages form specific phase differences, leading the entire system to oscillate in a first-order mode. As the flow develops from near-stall to stall, axial momentum decreases further, reducing the main flow’s ability to drive blockages downstream through convection. Consequently, the blockage accumulates during the circumferential propagation process until the stall onset. Based on the above mechanism, this study proposes factors describing the size of the backflow zone, shedding frequency, and convection velocity to characterize blockage dynamics, identifying critical values that represent the stall onset.