Supersonic Flutter Analysis Based on Three-Dimensional Local Piston Theory with Viscous Correction

Traditional supersonic flutter analysis methods exhibit inherent limitations owing to their inability to account for viscous effects and failure under nonzero angle of attack (AOA) conditions. This research carried out a three-dimensional (3-D) discretization form of local piston theory (3D-LPT). An iterative viscous correction method based on the supersonic boundary-layer theory is proposed. With the contribution of 3D-LPT with viscous correction, a supersonic flutter analysis method based on an aerodynamic-structure tightly coupled state-space model was established. Then, supersonic flutter wind tunnel tests were conducted across multiple AOA conditions, followed by the validation of the proposed method and comparative analyses of this method, an LPT with viscous correction method with conventional viscous correction, and an inviscid Euler-based local piston theory method. The results demonstrate that the proposed method is an efficient and highly accurate tool for evaluating the flutter characteristics of supersonic aircraft in the preliminary design phase, with a significantly higher accuracy than traditional methods under nonzero-AOA conditions and practical applicability to 3-D configurations.