Non-Linear Aeroelastic Behavior of Large Horizontal Axis Wind Turbines: A Multibody System Approach

GEBHARDT C. G.; PREIDIKMAN S.; JØRGENSEN M. H.; MASSA J. C.

Mar del Plata, Argentina

Congreso; HYFUSEN 2011 - 4º Congreso Nacional - 3º Congreso Iberoamericano: Hidrógeno y Fuentes Sustentables de Energía; 2011

Instituto de Energía y Desarrollo Sustentable (IEDS)

This paper shows the development of a flexible multibody model, which coupled with an existing aerodynamical model, is used to numerically simulate the non-linear aeroelastic behavior of large horizontal axis wind turbines. The model is rather general; different configurations could be easily simulated and it is primarily intended to be used as a research tool to investigate influences of detailed dynamic effects. It includes: i) a supporting tower; ii) a nacelle which contains the electrical generator, the power electronics and the control systems; iii) a hub where the blades are attached and connected to the generator rotating shaft; and, iv) three blades which extract energy from the airstream. The blades are considered flexible, and their equations of motion are discretized in the space domain by using beam finite elements capable of taking into account the non-linearities coming from the kinematics. The tower is also considered flexible, but its equations of motion are discretized by using the method of assumed-modes. The nacelle and hub are considered rigid, and are represented by taking into account the effects of the kinematical non-linearities. Due to the system complexity, the tower, nacelle and hub are modeled as a single kinematical chain and each blade is modeled separately. Constraint equations are used to connect the blades to the hub. The governing equations are differential-algebraic since ordinary differential equations and algebraic constraint equations are involved, due to the presence of rigid and discretized flexible bodies and linkage among bodies, respectively. All the equations are solved numerically and interactively in the time domain by using a fourth-order predictor-corrector scheme.