The new generation of large off-shore wind turbines present new challenges to their design, from their extreme strength requirements on their foundations to the very high speed of the wing tips. We are mainly concerned with the assessment of aeroelastic effects in the very long (over 100m in diameter) flexible composite blades, and in the integration of active load control mechanisms that improve performance and increase fatigue life.

Sponsors of our research in this area include EPSRC, the National Research Foundation, Singapore, and the Spanish National Centre for Renewable Energy (CENER).

Current projects

MAXFARM: Maximizing Wind Farm Aerodynamic Resource via Advanced Modelling

Simpson

Aeroservoelastic co-design of very flexible structures

Maraniello

Aeroelasticity of deformable wind-turbine airfoils in stalled conditions

Investigators: Alvaro Gonzalez, Rafael Palacios, Prof Mike Graham

The main objective of the proposed work is to develop a new aeroelastic tool, for deformable aerofoils or blade sections, including attached and separated flow and dynamic stall phenomena. During the project, simplified intermediate tools will be presented with obtained results, to evaluate the performance of the implemented models. The tools will be based on aerodynamic and structural models selected with a good compromise between accuracy and computa tional efficie ncy. The project is a collaboration with CENER.

Past projects

Model-based aeroservoelastic design and load alleviation of large wind turbines (2010-14)

Main investigator: Bing Feng Ng (link to PhD thesis)

This project developed an aeroservoelastic modelling approach for dynamic load alleviation in large wind turbines with trailing-edge aerodynamic surfaces. Time-domain aerodynamics are given by a linearised three-dimensional unsteady vortex-lattice method that allows better characterisation of aeroelastic responses under attached flow conditions and the direct modelling of lifting surfaces. The resulting unsteady aerodynamics is written in a state-space formulation suitable for model reductions and controller design, which does not rely on empirical corrections commonly found in Blade Element Momentum methods. Structural modules of the tower, potentially on a moving base, and the rotating blades are modelled using geometrically non-linear composite beams, which are linearised around reference conditions that have undergone arbitrarily-large structural displacements. This provided higher-fidelity efficient numerical models for linear robust controller design (LQG and Hinf), to achieve load alleviation in larger and more flexible wind turbines. The land-based NREL 5MW reference wind turbine is chosen to demonstrate the unified aeroservoelastic analysis framework.

Multiscale Analysis of Slender Composite Wings (2009-2014)

Main investigators: Julian Dizy (link to PhD thesis)

This project aimed at bridging the gap between the detailed information of geometric and material properties required for stress analyses on advanced composite blades and the low-order description required for the estimation of dynamic loads under actual operating conditions. It developed methods for homogenisation of periodic slender composite structures and demonstrated impressive gains in numerical efficiency against full 3-D simulations of the full structure.

Maximizing Wind Farm Aerodynamic Resource via Advanced Modelling