Numerical Stabilization for Flutter Analysis Procedure

Severe mode switching is often observed when the PK-method used in flutter analysis of complex aircraft configurations, particular nearly 100 vibrational modes are considered. In commonly commercial software NASTRAN, resulting eigenroots sorted an ascending order frequency. Therefore, appearance massive mode-switching instances cannot be avoided analyses, especially for engineering applications with real-world configurations. this study, as a post-processing procedure, extensive sorting capability was developed to compensate NASTRAN’s lack mode-tracking procedure between airspeed steps. The based on both eigenvalues and their corresponding eigenvectors. addition, numerical techniques computational fluid dynamics (CFD) were introduced improve convergence traditional PK-method. A hybrid approach applied initial guess reduced frequency, followed by deferred correction scheme PK-iteration process. Additionally, matching specifically addressed locking onto aerodynamics within PK iterations. addition iterations, damping iteration or modified g-method implemented extending solver. combination these special effectively improved stability iterations eigensolution process significantly misleading switching, minimizing risks flight.