Michael McWilliam

Technical University of Denmark | DTU · Department of Wind Energy

Rotary Airborne Wind Energy Systems (RAWES) are networks of wings that act as flying wind turbines. The power extracted from the wind can be transmitted to ground-based generators through open tensegrity structures. In recent years, there have been different approaches to the topology of the Tensile Rotary Power Transmission (TRPT) and prototype de...

Control co-design is a promising approach for wind turbine design due to the importance of the controller in power production, stability and load alleviation. However, the high computational effort required to solve optimization problems with added control design variables is a major obstacle to quantify the benefit of this approach. In this work,...

In wind turbine optimization, the standard power regulation strategy follows a constrained trajectory based on the maximum power coefficient. It can be updated automatically during the optimization process by solving a nested maximization problem at each iteration. We argue that this model does not take advantage of the load alleviation potential o...

In the preliminary phases of offshore wind farm development, very little information on project design are available for supporting financial valuation and site design. In this work, we develop a surrogate model for offshore wind support structure mass for input to techno-economic analysis that is based on a small set of input parameters. Using ref...

This work compares nodal, spline and interpolation parametrization schemes for wind turbine blade planform design. The comparison is done on a power coefficient maximization problem, where the aerodynamic properties of the blade are computed using the Blade Element Method. The problem is solved using a gradient-based interior-point method with anal...

Most small–medium-sized turbine studies have focused on presenting new design methods and corresponding performance improvements rather than detailed dynamic investigations. This paper presents comprehensive dynamic investigations of a straight and a swept-back blade for a 100kW turbine by performing modal analysis, dynamic load analysis, and flutt...

Post-Optimum Sensitivity Analysis (POSA) extends numerical design optimization to provide additional information on how the design and performance would change if various parameters and constraints were varied. POSA is challenging since it typically requires accurate gradients and gradient-based optimization problems that provide Lagrange multiplie...

This paper explores the preliminary design of the support structures for the IEA Wind Task 37 reference wind farm at the Borssele site III and IV. The study looks at two different design methods that might be used within larger wind farm system design optimization ( i.e. lay-out, electrical systems, etc. ). The first consists of a scaling tool that...

A novel wind turbine rotor optimization methodology is presented. Using an assumption of radial independence it is possible to obtain an optimal relationship between the global power (CP) and load coefficient (CT, CFM) through the use of Karush–Kuhn–Tucker (KKT) multipliers, leaving an optimization problem that can be solved at each radial station...

We present an analytical model for assessing the aerodynamic performance of a wind turbine rotor through a different parametrization of the classical blade element momentum (BEM) model. The model is named the Radially Independent Actuator Disc (RIAD) model, and it establishes an analytical relationship between the local thrust loading and the local...

This paper presents an analysis and optimization of Airborne Wind Energy Systems (AWESs), designed to maximize the Annual Energy Production (AEP) and, in the second part, the economic profit. A gradient-based optimization algorithm is used to perform the preliminary design of the main AWES sub-systems. A global sensitivity analysis is carried out t...

This paper presents the results from the first IEA Wind Task 37 aerodynamic optimization case study. 8 participants applied their optimization tools to a purely aerodynamic problem and the results were compared. Overall, the different tools produced widely different designs, while there was better agreement in the improvement achieved. This highlig...

We present an analytical model for assessing the aerodynamic performance of a wind turbine rotor though a different parametrization of the the classical Blade Element Momentum (BEM) model. The model is named the Radially Independent Actuator Disc model (RIAD) and it establishes an analytical relationship between the local-thrust loading and the loc...

A novel wind turbine rotor optimization methodology is presented. Using an assumption of radial independence it is possible to obtain an optimal relationship between the global power- (CP) and load-coefficient (CT, CFM) through the use of KKT-multipliers, leaving an optimization problem that can be solved at each radial station independently. It al...

The aim of this work is to propose engineering models to include the external forces acting on the tether into the power estimation of an Airborne Wind Energy System flying crosswind. The influence of aerodynamic drag, centrifugal force and gravitational force on power production is investigated. These three types of external loading acting on the...

This paper presents analytic equations modelling the main physics and cost of a generic Airborne Wind Energy System flying crosswind. The power equation of a system that can handle ground and on-board generation is presented, under the assumption of steady-state flight. A structural and a take-off model are used to derive the key equations for the...

The highest renewable energy (RE) penetration markets in Europe offer important lessons that should be incorporated in the planning and design of the future wind power and grid systems in the transition towards 100% RE. As the overall wind power in a region increases, the value of that wind energy decreases and in some cases grid stability and comp...

This article presents a design study into the redesign of a wind turbine blade tip seeking to increase the energy production subject to the loads constraints of the existing blade. The blade shape is parameterized to allow for planform changes in the tip region with respect to chord, twist and blade length extension, and additionally three paramete...

An airfoil database was developed in the present work. The database includes a multivariate, unstructured grid, Radial Basis Function (RBF), optimization-compatible interpolator for airfoil aerodynamic coefficients. The database was designed to aid complex blade design optimizations carried out in a novel optimization framework, HAWTOpt2, being cur...

Passive Bend-Twist Coupling (BTC) can be used in blades to alleviate loads and generate more Annual Energy Production (AEP). However, BTC is inherently aero-elastic, thus difficult to incorporate into the design with sequential design process. Multi-disciplinary Design Optimization (MDO) is an attractive approach for overcoming these challenges. Th...

In optimal wind turbine design, there is a compromise between maximizing the energy producing forces and minimizing the absolute peak loads carried by the structures. Active flaps are an attractive strategy because they give engineers greater freedom to vary the aerodynamic forces under any condition. Flaps can be used in a variety of different way...

In optimal wind turbine design, there is a compromise between maximizing the energy producing forces and minimizing the absolute peak loads carried by the structures. Active flaps are an attractive strategy because they give engineers greater freedom to vary the aerodynamic forces under any condition. Flaps can be used in a variety of different way...

This work presents an integrated multidisciplinary wind turbine optimization framework utilizing state-of-the-art aeroelastic and strutural tools, capable of simultaneous design of the outer geometry and internal structure of the blade. The framework is utilized to design a 10 MW rotor constrained not to exceed the design loads of an existing refer...

The Design Engineering Mentorship Program (DEMP) is a five-day intensive training program focused on developing appropriate competencies in graduate students required to effectively teach engineering design at the undergraduate level. Evolution of the present program is discussed in context of feedback and observations from the now defunct Design E...

This paper presents the impact that theDesign Engineering and Design (DE&I) program offeredin 2013 has had in the Faculty of Engineering at theUniversity of Victoria. Through this program a pool ofnineteen graduate students were trained as DesignTeaching Assistants (DTAs). The purpose of this programis to train DTAs in engineering design principles...

This paper presents a novel aerodynamic model based on Lagrangian Vortex Dynamics (LVD) formulated using a Finite Element (FE) approach. The advantage of LVD is improved fidelity over Blade Element Momentum Theory (BEMT) while being faster than Numerical Navier-Stokes Models (NNSM) in either primitive or velocity-vorticity formulations. The model i...

This program is an initiative of the Chair in Design Engineering of the University of Victoria Faculty of Engineering to an NSERC mandate to improve engineering design instruction. To date, there are not enough qualified personnel to support design projects and help students. This problem will be more evident in the upcoming years when the number o...

Multi-disciplinary Design Optimization (MDO) has been successfully applied in the aerospace industry, so given the similarities to wind turbine design, the application of MDO techniques is a potential opportunity to improve wind turbine design. MDO attempts to solve for optimal design parameters by considering the performance of multiple discipline...

New design concepts for large flexible blades are needed to continue the trend towards ever larger turbines and continued economies of scale. Load alleviation based on building bend-twist coupling into the blades is an attractive concept because it can reduce the root bending moments and the fatigue damage in the blades with a negligible affect on...

Research has shown that design concepts based on advanced lay-ups can improve wind turbine blades. Adding carbon fiber reinforcement at outboard sections can make blades lighter reducing edge-wise bending loads. Adding biased fibers can introduce bend-twist coupling reducing the fatigue damage. Optimizations is a powerful tool that can be used to s...

The optimal location and configuration of wind farms in a large region is important information for policy makers, electricity system planners and wind farm developers. The model developed in this paper uses wind resource data, population data and transmission line locations to find the configuration that produces electricity at minimum cost. Sever...

Many researchers are exploring advanced wind turbine designs that incorporate vari- ous passive structural load alleviation strategies. All of these methods rely on physical behavior not resolved in conventional analysis methods. Strategies based on novel blade shapes (sweep and coning) rely on geometric nonlinearity. Other strategies rely on mater...

There is a substantial body of ongoing research improving the Blade Element Momentum (BEM) theory and applying it to the optimization of wind turbine rotors. Both of these developments challenge the suitability of fixed point iteration schemes being applied to advanced BEM models. This article explores the mathematical behavior of the BEM equations...

A new Blade Element Momentum (BEM) model is proposed for yawed wind turbine flows. This method differs from conventional methods in the use of correction factors for the induction. A set of results from potential flow methods is used to define a table of corrections over a wide range of operating conditions and locations within the flow field. The...

A study of the air flow around five different model vertical axis wind turbines has been undertaken using Particle Image Velocimetry (PIV) in a closed loop wind tunnel. Turbine models include a ‘standard Savonius’ design, a ‘deep’ blade and a ‘shallow’ blade and two blades with compound blade curvature. Measurements were obtained at six constant ph...

The engineering of wind turbines is not fully mature. There are still phenomena, particularly dynamic stall that cannot be accurately modeled. Dynamic stall contributes to fatigue stress and premature failure in many turbine components. The three dimensionality of dynamic stall make these structures unique for wind turbines. Currently flow visualiz...