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The nonlinear effects of dynamic and aerodynamic imbalance on the harmonic and chaotic motion of a horizontal axis wind turbine
Abstract
This investigation explores the dynamic and aerodynamic effects of imbalance on the motion of a horizontal axis wind turbine (HAWT). The nonlinear dynamic equations describing the motion of a HAWT with both static and dynamic imbalance are derived and investigated. A perturbation scheme is developed to solve a simplified version of the nonlinear differential equations. The static imbalance of the DOE's test wind turbine has been calculated and its effects have been identified as 60% of the observed once per azimuthal revolution (1P) variance in the low speed shaft torque (LSST) spectrum. It was also found that a small amount of blade pitch imbalance, 1 degree, is sufficient to account for the remaining 40% variance observed in the 1P low speed shaft torque field data. The perturbation analysis prompted a fully nonlinear numerical investigation of both the statically and dynamically imbalanced rotor dynamics. The 1P variation in LSST due to mass imbalance was found to cause chaotic motion. The necessary system parameters and/or operating conditions which resulted in classic chaotic responses in both the yaw and teeter motions were identified.
Subject Area
Mechanical engineering|Aerospace materials|Mathematics
Recommended Citation
Borg, John Pfaff, "The nonlinear effects of dynamic and aerodynamic imbalance on the harmonic and chaotic motion of a horizontal axis wind turbine" (1996). Doctoral Dissertations Available from Proquest. AAI9638931.
https://scholarworks.umass.edu/dissertations/AAI9638931