عنوان مقاله [English]
In this study, the instability boundary of a wing - in the incompressible flow regime has been considered, using Peter's aerodynamics, and compared with the result obtained from the Theodorson aerodynamic.To this aim, the lift coefficient, based on Peter's theory in the frequency domain, is obtained, at first, for a pure plunging motion. Then, real and imaginary parts of the lift and moment are plotted versus reduced frequency and compared with those from the Theodorson aerodynamic. It can be seen that, with a fewer number of aerodynamic states in Peter's theory (N=5) , there will be good agreement between the two theories. In addition, equations corresponding to mass, stiffness and damping matrices from Peter's theory have been obtained. To do this, two models, including a typical section and beam, are used for structural modeling. Finally, the flutter boundary is determined using $p-k$ and $p$ methods and the results compared with those from the Theodorson aerodynamic. Results show good agreement between the two theories.