###### Abstract
[PERSON] and [PERSON] [10] performed a linear analysis for a _cantilever pipe_ to investigate the effects of passive piezoelectric damping with a load resistance on the flutter speed. They demonstrated that the mechanical stiffening effects of the open-circuit cause an increase in the flutter speed compared to the short-circuit. The authors showed that the larger the piezoelectric electromechanical coupling coefficient, the higher the flutter speed. For the open circuit case, it is indicated that an increase in the piezoelectric capacitance is accompanied by a decrease in the flutter speed. [PERSON] et al. [11] presented a frequency domain analysis and experimental validations for a two-degree-of-freedom typical section as a wing-based _piezoareelastic_ energy harvester. They focused on the problem of harvesting energy at the flutter boundary and analyze the effects of the piezoelectric coupling on the linear flutter speed. In their mathematical modeling, they introduced a piezoelectric coupling to the plunge degree of freedom and considered a load resistance in the electrical field. They presented the modified lumped-parameter aeroelastic equations. As for the aerodynamic lift and moment modeling, a two-dimensional unsteady representation is based on the [PERSON]'s approach. It is indicated that a good agreement between the mathematical model and the experimental measurements is obtained. It is shown that the generated voltage increases when increasing the electrical load resistance. Furthermore, there is an optimum value of the electrical load resistance in which the harvested power is maximized. [PERSON] et al. [12] presented a time-domain piezoaroelastic modeling and numerical simulations of a generator wing with embedded piezoceramics for continuous--and segmented-electrode configurations. Their wing-based piezoaroelastic energy harvester model is obtained by combining an electromechanically coupled finite element model based on the classical plate theory with an unsteady vortex-lattice model [13] representing the aerodynamic loads. They reported that, when using segmented electrodes, torsional motions of the coupled modes become more important and therefore change the flutter speed which improves the broad band performance of the harvester. [PERSON] and [PERSON] [14] presented theoretical analysis of harvesting energy from the flutter of a flexible plate subjected to an axial flow. They presented _local and global stability_ analyses based on the global coupled electromechanical equations of motion. Other linear analyses are performed in [15; 16]. The authors presented theoretically and experimentally a guideline to design piezoaroelastic energy harvesters that can generate energy at low freestream velocities. The effects of varying the mass and stiffness parameters on the linear flutter speed and frequency are investigated. They reported that the linear flutter speed is more sensitive to the flap center of mass location, the flap mass moment of inertia, and the flap mass. In [15; 16], a semi-empirical nonlinear model is used to determine the unsteady aerodynamic loads for large flap deflections. [PERSON] et al. [17] considered an aeroelastic system for which they study the possibility of harvesting energy from both piezoelectric transduction and electromagnetic induction, named _hybrid energy harvesting_. The authors presented the linear governing equations of a hybrid aeroelastic energy harvester and investigate in detail the effects of the electrical and aeroelastic properties on the linear flutter speed and performance of the harvester at the flutter boundary. It is demonstrated that a reduction in the radius of gyration and frequency ratio and an increase in the eccentricity result in a decrease in the linear flutter speed and an increase in the harvested power at the flutter boundary. A three-degree-of-freedom hybrid (piezoelectric and electromagnetic) aeroelastic energy harvester that includes _control surface_ in the airfoil (flap effect), was considered by [PERSON] et al. [18].