The influence of aerodynamic derivatives on flutter

The influence on flutter instability of each of the aerodynamic derivatives, which were obtained by pressure measurement on the side surface of 2-D rectangular cylinders with various side-ratios B/D (B is the chord length, D the height) between 5 and 20 under the 1DOF heaving/torsional forced vibration, is discussed through a “step-by-step method” developed here. With increasing B/D, the role of the coupled terms of the aerodynamic derivatives, in particular A1∗ and H3∗, becomes more important in flutter instability. On the other hand, the flutter instability is almost characterized by A2∗ for bluff rectangular cylinders with B/D such as 5 or 8 or 10.