Analysis of Flow Control in Compressor Stator by Steady and Pulsed Jets Based on Numerical Simulations and POD Method

This study introduces steady and pulsed jets at the endwall of an annular compressor stator cascade. Through numerical simulation of actively controlled unsteady flow fields, combined with Proper Orthogonal Decomposition (POD) for spatiotemporal modal analysis of the primary flow structures, the flow evolution mechanisms and control characteristics under both jet modes are systematically revealed. The research demonstrates that the effectiveness of jet control exhibits significant axial position sensitivity: when applied upstream of the separation point on the suction side of the blade cascade, the steady jet achieves a maximum total pressure loss reduction of 9.2%, while the pulsed jet attains 10.2%. The pulsed jet shows notable advantages, more effectively suppressing the development of passage vortices and trailing-edge shedding vortices, weakening vortex intensity and range, and promoting ordered turbulence fluctuations through frequency locking effects. POD analysis further indicates that the dominant flow structures are concentrated in the first four modes, with corresponding time coefficient frequencies matching the fundamental frequency and its harmonics. The time coefficients of the pulsed jet display a quasi-sinusoidal distribution, indicating better coupling with the flow field. Additionally, the pulsed jet redistributes modal energy, weakening the first-order mode while enhancing the energy proportion of other dominant modes. By integrating active flow control with spatiotemporal modal decomposition, this study not only reveals the superiority of pulsed jets but also provides new methodologies and foundations for mechanistic analysis and optimization of compressor flow control.