机翼跨声速抖振数值模拟及模态分析

Transonic buffet flow over a wing is a classical complex and unstable flow case, and the research on unsteady characteristics and instability mechanism has significant engineering and academic values. By means of numerical simulation and Dynamic Mode Decomposition (DMD) analysis, this paper studies the characteristics and the dominant modes of buffet flow over wings, such as CRM (Common Research Model) wing. The results by the Unsteady Reynolds Averaged Navier-Stokes (URANS)method indicate that the 3-D transonic buffet flow is dominated by multiple instability patterns with broadband spectrum. Besides the shock oscillation along the chordwise, the spanwise oscillation is also occurred, which both display in low-frequency manners. While the high-frequency response at the wingtip may be caused by the coupling of oscillating shock and K-H type instability, the results from DMD modes show that the factors of sweep and aspect ratio result in the spanwise instability of the shock. This study has potential meaning to perform physical modeling, control and to understand complex aeroelastic phenomena associated with transonic buffet flow.