Flutter mechanism and flutter modality investigation for thin plate sections

The flutter-driving mechanism and the flutter modality of the classical coupled flutter phenomenon for thin plate sections are investigated by the two-dimensional 3DOF coupling flutter analysis method (2d-3DOF method). The results indicate that the classical coupled flutter is driven by the negative aerodynamic damping which mainly comes from the coupling effects between torsional and heaving motions. The calculated flutter modality vector at the flutter onset reveals that the participation level of heaving motion in the flutter phenomenon is very high, which implies strong coupling effects between motions in different degrees of freedom. Finally the relationships between flutter modality, frequency ratio and flutter performance are analyzed.