Comparative analysis of corner separation controlled by steady jets and oscillating jets on a compressor cascade

To mitigate corner separation in compressor cascades, this study compares the control effects of single oscillating jets (SOJ), arrayed oscillating jets (AOJ), single steady jets (SSJ), arrayed steady jets (ASJ), and full-span steady jets (FSJ) configured on the blade surface. The results indicate that steady jet schemes can only reduce the overall total pressure loss within a limited range of incidence angles. In contrast, oscillating jet schemes can reduce the overall total pressure loss over a wider range of incidence angles and offer better active control effects, with a maximum loss reduction of about 40% in the AOJ scheme. Additionally, all jet schemes can reduce the vorticity of the passage vortices and concentrated shedding vortices in the corner region through the jet momentum injection effect, thereby reducing corner losses. However, in SSJ and SOJ schemes, the reduction of corner separation eventually results in higher blade losses. Furthermore, in ASJ, AOJ, and FSJ schemes, the increased shear interaction between the jet and mainstream raises the trailing-edge shedding vortex's structure size and vorticity, which increases blade mixing losses. Finally, the cascade flow field in steady jet schemes shows almost no significant pulsation characteristics. In contrast, the flow field in oscillating jet schemes exhibits higher-frequency pulsations at the excitation frequency, and the two-norms and growth rates of the main modes through dynamic mode decomposition in the corner region significantly increase, indicating a more effective jet momentum injection effect.