Numerical Simulation Study on Coupling Relationship of Coherent Structure in High-Load Blade Tip

This study investigates the coherent structures in the tip region of a planar cascade with tip clearance under high incidence conditions using Large Eddy Simulation (LES). The dominant coherent structures are identified as the tip leakage vortex and suction-side separation vortex. By analyzing their transient flow characteristics through Fast Fourier Transform (FFT), the dominant frequencies of both vortices are captured. Unsteady flow control is implemented by adopting the dominant frequency of the separation vortex as the excitation input, enabling a systematic investigation into the modulated coherent structure dynamics, spectral evolution of the tip flow field, and the underlying mechanisms of unsteady control effectiveness. Furthermore, the coupling mechanisms between excitation frequency-driven flow modulation and the interactions of the tip leakage vortex and separation vortex are rigorously analyzed, providing insights into frequency-based strategies for stabilizing tip flow aerodynamics and mitigating losses.