Offshore wind power generation is a key component of the UK's commitment to deliver 15% of gross final energy consumption from renewable sources by 2020. Efforts to meet this target are prompting the design of ever larger turbines in order to capture more energy from the wind. However, as these structures grow taller, they become increasingly vulnerable to violent gusts of wind and other turbulent flow phenomena that are the primary cause of severe turbine damage. Advance warning of such gusts will enable turbine control systems to take preventative action, and so the ability to predict the strength of an oncoming gust is widely regarded within the wind energy industry as being a problem of critical importance. This research project will seek to overcome this problem by demonstrating a system that can accurately forecast the velocity profile of an oncoming wind, given only limited spatial measurements from state-of-the-art light detection and ranging (LIDAR) units. This approach will exploit recent interdisciplinary advances in the application of optimal estimation techniques, from the control systems community, to fluid-mechanical systems governed by the Navier-Stokes equations. The research will draw upon the PI's existing expertise in dynamical estimation of fluid flows and the project results will feed into the host institute's current industrial collaboration with Vestas Wind Systems, who have agreed to provide the data and technical support required to maximise research impact.

The Department for Transport forecasts that by 2020 the number of passengers using UK airports will be around 400 million, compared to 200 million today. Aviation noise represents a major obstacle to the future expansion of many existing airports and thus the growth in the capacity of the air transport system. In 2001 the Advisory Council for Aeronautics Research in Europe (ACARE) set out a target to reduce perceived aviation noise to one half of the current level by 2020. To achieve the ACARE target by the year 2020 a "technology breakthrough" is urgently needed. Wind turbine manufacturers also require new technology for the significant reduction of aerodynamic noise in order to make wind turbines more acceptable to communities, especially concerned with onshore wind farms. Such a technology breakthrough can only be achieved through a fundamental evaluation and re-design of aerofoils, particularly the "leading edges" (LE), since upstream turbulent flows impinging on the LE of an aerofoil is believed to be the dominant source mechanism of broadband noise in turbofan engines (rotor wakes scattered by the outlet guide vanes - OGV) and wind farms (upstream rotor wakes scattered by the downstream turbine blades). In turbofan engines, it is envisaged that new LE design would be applied to the OGV since noise reductions can only be achieved by modifying the OGV response or the rotor wake turbulence (much more difficult). The proposed 30-month research project aims to develop and investigate new aerofoil LE designs for the reduction of the broadband noise generated by the interaction between the aerofoil's LE and impinging turbulent flows, whilst minimising its impact on aerodynamic performance. The new aerofoil LE designs will be constructed by combining "smooth" spectral (wavy) serrations with multiple wavelengths, which has never before been attempted. In this project, a coordinated aeroacoustic and aerodynamic study of this new LE topology is proposed, particularly focused on the effects of smaller wavelengths (comparable to the impinging turbulence length scale), which are expected to be effective in reducing noise without making a significant impact on aerodynamic performance. The proposed project will take full advantage of the experimental and computational expertise of the two investigators. The successful outcome of this project will lead to a new aerofoil LE design that offers maximum noise reduction and minimum aerodynamic penalty. The commercial and academic impact of this work is potentially substantial. The proposed research programme will be largely split and managed in four stages: 1) testing baseline aerofoil models for calibration and validation purposes; 2) identifying the most effective Fourier modes of the proposed LE serrations with respect to noise reduction; 3) combining the identified individual Fourier modes into an integrated spectral LE design (8 models in total) and testing the aerodynamic performance as well as the overall noise reduction; and 4) further understanding and improving the most favourable design found in Stage 3 via detailed numerical simulations. The experimental measurements will be performed in our AWT (anechoic wind tunnel) facilities. The numerical simulations will be carried out by using CAA (computational aeroacoustics) techniques. The CAA and AWT activities are closely coordinated and mutually supportive to ensure maximum value to the project. The proposed study will be based on a NACA65(1)-210 aerofoil with the Reynolds number up to 1.1x10^6 and the Mach number of 0.3 to 0.6. The length scales of impinging free-stream turbulence will be determined and generated in accordance with the guidelines from the industrial partners representing the aero-engine and wind turbine industries.

Adaptive Aerostructures for Power and Transportation Sustainability (AdAPTS) is an Early Career Fellowship research project which will advance an ambitious new approach to the design of aerostructures by harnessing the adaptability of compliance-based morphing to continuously optimise aerodynamic performance. This will allow for greener and more sustainable fixed and rotary wing transportation and wind turbine power generation through reduced aerodynamic drag, increased efficiency and improved resilience to changing operating conditions. Compliance-based adaptive aerostructures are designed to exhibit structural and material flexibility that allows them to change their shape in a smooth and continuous manner. These changes in shape are isolated to certain desired motions in specific areas of an aerodynamic surface, for example the amount of curvature at the rear of an aerofoil, to allow for targeted changes in shape while retaining overall strength. These changes in shape improve the ability of the wing or blade to produce lift, minimise the amount of drag generated, and allow for continuous adaptation to changing operating conditions. Initial work has shown that the family of compliance-based morphing devices developed by the PI can provide significant improvements in performance of 5-25%. While the potential benefits are promising, much work remains to make compliance-based morphing a viable solution. These types of structures are poorly understood, and the underlying technologies need significant development. The poor understanding of the performance and behaviour of these structures is due to their compliant nature, which means that the structural, aerodynamic, and actuation characteristics are all highly coupled - with the aerodynamic loading affecting the actuated shape, which in turn affects the aerodynamics. This coupling requires simulation of all of the physics involved in a cohesive, coupled manner. Furthermore, the structural, material, and actuation technologies used to achieve these smooth and continuous deformed shapes are novel, and therefore significant effort is needed to mature them to the point where they can be used in real-world applications. Finally, industry partners in the fixed wing, rotary wing, and wind turbine fields see the potential in these technologies, but because they are so novel and different from current approaches, work needs to be done to show the specific, quantitative improvements in performance that these technologies can achieve for their applications. To address the three sides of this problem, AdAPTS will undertake an ambitious research programme with three parallel streams of work that will: 1.) create a fully comprehensive analysis framework to better understand the hierarchical, coupled performance of compliance-based morphing structures from the bottom up, 2.) rapidly mature the proposed morphing technologies, and 3.) work directly with industry to analyse and design adaptive structures for their products, and to predict the achievable improvements in performance.

High performance fibre-reinforced polymer composites are the current state-of-the-art for lightweight structures and their use is rising exponentially in a wide range of applications from aerospace to sporting goods. They offer outstanding mechanical properties: high strength and stiffness, low weight, and low susceptibility to fatigue and corrosion. The use of high strength, high stiffness materials in fibre form mitigates the tendency for premature brittle failure, enables components to be formed at low or moderate temperatures, and enables anisotropic designs to target the primary load-carrying demands. Fibres are particularly efficient in uniaxial tension but, under compression, composites suffer a range of failures typically associated with fibre micro-buckling or kinking, linked to matrix or interfacial issues; these mechanisms couple in a complicated way at a variety of physical lengthscales. Often, these types of failure determine the practical usage of composites and set design limits well below the expected intrinsic performance of the constituent fibres. On the other hand, new constituents and processes are becoming available that enable the directed assembly of composite structures, controlled across a much wider range of lengthscales than previously possible. In principle, then, composite materials should be redesigned to take advantage of these opportunities to supress or redirect the failure process in compression. Natural materials, such as wood and bone, are fully hierarchical, with precise structural features resolved at every possible magnification. Artificial composites lack this dexterity but can exploit intrinsically superior constituents. The increasing ability to visualise, calculate, and control structures, including with quantitative precision, will allow a new generation of composite materials to be developed. The ambition is to realise the full intrinsic potential of the fibres by designing such hierarchical systems for compression, from first principles, exploiting the latest developments in materials, processing, characterisation, and modelling of mechanistic processes. This programme focusses on the challenge of improving the absolute performance of composites in compression, both to address practical limitations of current materials, and as a demonstration of the value of quantitative hierarchical materials design. Tools and materials developed during this programme will be useful in a range of other contexts. The work will develop and embed structure at every lengthscale from the molecules of the matrix, to the lay-up of final components, using new constituents and new architectures, designed with a new analytical framework. The programme will benefit from a highly creative and interdisciplinary approach amongst the core project term, amplified by contributions from leading international advisors and collaborators. An extensive group of industrial partners will contribute to the project, and help to develop the outputs, building on concept demonstrators designed during the programme. The scientific and technical results will be widely disseminated nationally and internationally, helping to ensure UK leadership in this key field.

We will launch a new CDT, focused on composite materials and manufacturing, to deliver the next generation of composites research and technology leaders equipped with the skills to make an impact on society. In recent times, composites have been replacing traditional materials, e.g. metals, at an unprecedented rate. Global growth in their use is expected to be rapid (5-10% annually). This growth is being driven by the need to lightweight structures for which 'lighter is better', e.g. aircraft, automotive car bodywork and wind blades; and by the benefits that composites offer to functionalise both materials and structures. The drivers for lightweighting are mainly material cost, fuel efficiency, reducing emissions contributing to climate change, but also for more purely engineering reasons such as improved operational performance and functionality. For example, the UK composites sector has contributed significantly to the Airbus A400M and A350 airframes, which exhibit markedly better performance over their metallic counterparts. Similarly, in the wind energy field, typically, over 90% of a wind turbine blade comprises composites. However, given the trend towards larger rotors, weight and stiffness have become limiting factors, necessitating a greater use of carbon fibre. Advanced composites, and the possibility that they offer to add extra functionality such as shape adaptation, are enablers for lighter, smarter blades, and cheaper more abundant energy. In the automotive sector, given the push for greener cars, the need for high speed, production line-scale, manufacturing approaches will necessitate more understanding of how different materials perform. Given these developments, the UK has invested heavily in supporting the science and technology of composite materials, for instance, through the establishment of the National Composites Centre at the University of Bristol. Further investments are now required to support the skills element of the UK provision towards the composites industry and the challenges it presents. Currently, there is a recognised skills shortage in the UK's technical workforce for composites; the shortage being particularly acute for doctoral skills (30-150/year are needed). New developments within industry, such as robotic manufacture, additive manufacture, sustainability and recycling, and digital manufacturing require training that encompasses engineering as well as the physical sciences. Our CDT will supply a highly skilled workforce and technical leadership to support the industry; specifically, the leadership to bring forth new radical thinking and the innovative mind-set required to future-proof the UK's global competitiveness. The development of future composites, competing with the present resins, fibres and functional properties, as well as alternative materials, will require doctoral students to acquire underpinning knowledge of advanced materials science and engineering, and practical experience of the ensuing composites and structures. These highly skilled doctoral students will not only need to understand technical subjects but should also be able to place acquired knowledge within the context of the modern world. Our CDT will deliver this training, providing core engineering competencies, including the experimental and theoretical elements of composites engineering and science. Core engineering modules will seek to develop the students' understanding of the performance of composite materials, and how that performance might be improved. Alongside core materials, manufacturing and computational analysis training, the CDT will deliver a transferable skills training programme, e.g. communication, leadership, and translational research skills. Collaborating with industrial partners (e.g. Rolls Royce) and world-leading international expertise (e.g. University of Limerick), we will produce an exciting integrated programme enabling our students to become future leaders.