Flutter Transition of Two-Bay Panels with Shock Impingement

For multibay panels, the structural coupling between the adjacent panels dominates their aeroelastic instability. Given the dominant structural coupling, the complicated flowfield imposed by shock impingement might significantly influence the aeroelastic performance. This study investigates the flutter characteristics of a two-bay panel subjected to a shock impingement. A modified Rayleigh–Ritz method is employed to discretize the motion equation, which is then numerically solved to obtain the aeroelastic response. The proper orthogonal decomposition (POD) is applied to further extract spatial features of panel responses. Based on the flutter amplitude, flutter shape, and mechanical energy, three distinct flutter types, mainly characterized by different flutter intensities of the front and rear bay panels, have been identified. Depending on the mode shapes and corresponding energy distribution, the POD modes further depict the characteristics of different flutter types and their transition. Moreover, the correlation analysis on the POD modes between the structural deflection and aerodynamic pressure reveals the underlying fluid–structure coupling mechanism for the flutter transition, highlighting the crucial role of the phase difference between aerodynamic and structural modes. The impacts of shock parameters, including shock strength and impingement location, on the flutter characteristics are also evaluated, which exhibit complicated non-monotonic effects on the flutter/transition boundary and flutter energy.