Nonlinear vibration characteristics of three-blade wind turbines are theoretically investigated. The wind turbine is modeled as a coupled system, consisting of a flexible tower with two degrees-of-freedom (2DOF), and three blades, each with a single degree of freedom (SDOF). The blades are subjected to steady winds. The wind velocity increases proportionally with height due to vertical wind shear. The natural frequency diagram is calculated with respect to the rotational speed of the wind turbine. The corresponding linear system with parametric excitation terms is analyzed to determine the rotational speeds where unstable vibrations appear and to predict at what rotational speeds the blades may vibrate at high amplitudes in a real wind turbine. The frequency response curves are then obtained by applying the swept-sine test to the equations of motion for the nonlinear system. They exhibit softening behavior due to the nonlinear restoring moments acting on the blades. Stationary time histories and their fast Fourier transform (FFT) results are also calculated. In the numerical simulations, localization phenomena are observed, where the three blades vibrate at different amplitudes. Basins of attraction (BOAs) are also calculated to examine the influence of a disturbance on the appearance of localization phenomena.
Parametric Instability and Localization of Vibrations in Three-Blade Wind Turbines
Contributed by the Design Engineering Division of ASME for publication in the JOURNAL OF COMPUTATIONAL AND NONLINEAR DYNAMICS. Manuscript received July 6, 2017; final manuscript received March 22, 2018; published online May 17, 2018. Assoc. Editor: Brian Feeny.
- Views Icon Views
- Share Icon Share
- Cite Icon Cite
- Search Site
Ikeda, T., Harata, Y., and Ishida, Y. (May 17, 2018). "Parametric Instability and Localization of Vibrations in Three-Blade Wind Turbines." ASME. J. Comput. Nonlinear Dynam. July 2018; 13(7): 071001. https://doi.org/10.1115/1.4039899
Download citation file:
- Ris (Zotero)
- Reference Manager