About modeling of resonance of helicopter rotational propeller

The mathematical model of helicopter propeller, which is rotating in air, is used. The description of propeller construction is made. The mathematical model of propeller is consists of fifteen equations, also the equations of gas motion and boundary, initial conditions are added. The finite element method is used for discretization of mathematical model, for investigation of mathematical model. The first task about free vibration of helicopter propeller is solved. The frequencies and shapes of free vibrations are found. The solution of second task about helicopter rotational propeller in air shows additional periodic pressure of air on the screw surface after some angular velocity of rotation of propeller. The comparison of the frequency of pressure variation with the frequencies of free vibrations shows the resonance of the propeller. The solution of this task shown cause of the actual destruction of the helicopter propeller and the solutions to this problem. The optimization of propeller construction is connect with the variations of geometric parameters of cross section of the propeller.