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The panel flutter is concentrated with aerospace researchers, because of fatigue failure on structures. The usage of the numerical simulation is good company with analytical method. The 2D cylindrical panel flutter is simulated with navierstocks equations for fluid flow with finite volume theory. Also, Simulation is prepared with piston theory for analytical solution. Comparison of full numerical finite volume and assume mode method in post flutter domain is produced. Non-linear shell with the effect of in-plane load, thermal load and aerodynamic load with 3rd order piston theory is modeled to solve with assume mode method. The numerical method is 4th order rung-kutta to solve ODEs. With increasing shell camber, limite cycle oscillation change to random motion. The effect of expansion waves made decrease in second half of shell in analytical method in compare to numerical. The most important output depend on equal result for flat plate and different result on curve plate with numerical and analytical method. With increasing shell camber, limite cycle oscillation change to random motion. The effect of expansion waves made decrease in second half of shell in analytical method in compare to numerical. Amplitude of oscillation and flutter speed respectively is increase and decrease in numerical method despite of analytical one.

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Variable pitch propeller (VPP) are used in advanced helicopters, in order to achieve greater efficiency, better stability and achieve higher altitudes. This study is going to assess the behavior of VPP propeller with coupled non-linear displacement in three degrees of freedom. Accordingly, the behavior of this type of propeller with Changes of elastic axis distance, Length, mass, speed, polar radius of gyration, Stiffness in three degrees of freedom, and pitch have been investigated. In this paper, Gallerkin method is used to extract natural frequencies and the results were evaluated with the results reported by other researchers. The results show convergence and accuracy of the used method. In this study, it was found that parameters of mass, length and rotational speed of the propeller have effect on the natural frequencies, and all modes of vibration. However, other parameters except for the pitch angle effect on the odd or even number of frequency modes. It was also found that the pitch angle in the static mode does not effect on natural frequencies but in the case of rotation of propeller, affect on natural frequency of vibration modes as sine or cosine form.