Model-based Aeroservoelastic Design and Load Alleviation of Large Wind Turbine Blades

This paper presents an aeroservoelastic modeling approach for dynamic load alleviation in large wind turbines with trailing-edge aerodynamic surfaces. The tower, potentially on a moving base, and the rotating blades are modeled using geometrically non-linear composite beams, which are linearized around reference conditions with arbitrarily-large structural displacements. Time-domain aerodynamics are given by a linearized 3-D unsteady vortexlattice method and the resulting dynamic aeroelastic model is written in a state-space formulation suitable for model reductions and control synthesis. A linear model of a single blade is used to design a Linear-Quadratic-Gaussian regulator on its root-bending moments, which is finally shown to provide load reductions of about 20% in closed-loop on the full wind turbine non-linear aeroelastic model

Aeronautical Engineering: A special bibliography with indexes, supplement 72, July 1976

This bibliography lists 184 reports, articles, and other documents introduced into the NASA scientific and technical information system in June 1976

Load Reduction Using Rapidly Deployed Trailing-Edge Flaps

This thesis details investigations into the aerodynamic properties of a small, rapidlyactuated, actively controlled trailing-edge ap and the potential of such a device to alleviate the unsteady loading experienced by wind turbine blades due to atmospheric turbulence and the atmospheric boundary layer, although such a device would have potential applications in other elds such as rotorcraft. The main goals of this work were to investigate whether aerodynamic loadings could in fact be alleviated by the use of a small trailing-edge ap using only measurements of the unsteady lift on the wing as a control input and to assess such a device's capacity to reject atmospheric disturbances with both numerical and experimental work, carried out in the Aeronautics Department at Imperial College London. The numerical work covered in the thesis comprises the results of linear and nonlinear aerodynamic and control simulations (e.g. PID, LQG controllers) and the results of computational uid dynamics (CFD) simulations using the commercial package FLUENT. The thesis also lays out the results obtained from testing an experimental prototype in the Hydrodynamics Laboratory in the Aeronautics Department. This prototype successfully rejected intentionally introduced ow disturbances from the vortex street of a square block upstream of the wing and the application of control provided a very signi cant reduction in the unsteady loading experienced by the wing. The ndings show the potential of this method of load control for the rejection of unsteady aerodynamic loading by the sole use of measurements of the wing loading and this has been demonstrated both theoretically and experimentally. The work is closed with a conclusion and suggestions for future research proposals