Next-generation aircraft are likely to require significant changes in technology to meet ambitious targets on fuel burn, CO2, NOX and noise emissions. Integrated computer-aided engineering is a key enabler to mitigate the risk coming with disruptive change and new design concepts. Moreover, the long-term vision of digital aircraft design and certification, to reduce reliance on wind tunnel and in-flight testing, requires leaps in highest-fidelity flow simulation. We revisit a grand challenge of aircraft aerodynamics using both state-of-the-art industrial and next-generation simulation tools enabled for the identification of coherent flow structures targeting the mechanisms leading to transonic wing shock buffet and constituting the instability, which despite intensive research efforts remains controversial. Shock buffet manifests itself as a flow instability in high-speed flight with detrimental effects on the aircraft performance, economic efficiency, and ultimately passenger safety. A vast amount of literature on flow instability exists, yet analysis of practical flows relevant to the aerospace industry is limited and often confined to simplified cases. Two key technology demonstrations provide the background to the work. The first is a recent global stability analysis of transonic shock buffet flow with three inhomogeneous spatial directions on an industry-relevant test case using an industry-grade computational fluid dynamics (CFD) solver suite and a Reynolds-averaged Navier-Stokes (RANS) aerodynamic model. However, high confidence in industry-standard CFD solutions is given only in a small region in the operating flight envelope near the cruise point due to the unavailability of general models to predict turbulent separated flow. Hence, the second recent key achievement is high Reynolds number direct numerical simulation (DNS) of supercritical transonic aerofoil flow, which also provides access to global modes. The premise of the work programme is that significant new elements, relying on high-performance computing and advanced numerical flow analysis, are in place to develop next-generation buffet prediction schemes suitable for next-generation transonic wings. We investigate global and resolvent mode analysis across the range of aerodynamic models (from RANS to DNS) applied to low-drag configuration (swept, laminar flow, supercritical) aerofoils and wings, culminating in a modern long-range, wide-body aircraft wing geometry. The practical aim is to develop robust, cost-effective methods to determine the buffet boundary of the wings of the future. Along the way, we will learn more about the physics of shock-induced unsteadiness and the mechanisms leading to shock buffet in the flow around transonic wings.

The potential for exploiting synthetic jet actuators to delay and control boundary-layer separation in conditions akin to those on aircraft components operating in high-load conditions has attracted much interest in recent years. However, the fundamental mechanism by which synthetic jets interact with incipiently separated turbulent boundary layers subjected to strongly adverse pressure gradient is yet to be fully understood before cost-effective operational flow-control solutions can be sought. This proposal seeks funding for a joint programme of work between groups at Manchester University and Imperial College London, which would exploit complementary strengths and facilities at the two universities. The programme aims to employ a combined experimental (Stereo PIV and other conventional measurement techniques) and computational approach (LES and LES/RANS hybrid modelling) to study the detailed interaction mechanisms, so as to derive generically valid guidelines on optimal separation control in a practical setting. The outcome of the research would be of value to both the academic community and aerospace industry, the latter striving to evolve engineering solutions to flow management with a minimum of moving parts and energy input.

Recent years have seen increasing interest in the use of thick-section composites for safety-critical components in, for example, primary aircraft structure and fan blades in aero engines. All such components are required to undergo non-destructive evaluation (NDE) during manufacture; this is time consuming and NDE throughput is stretched to its limit internationally. Current composite Non-destructive Evaluation (NDE) is based on a qualitative empirical approach where a single normal-incidence ultrasonic probe is used to estimate the average ultrasonic attenuation from the amplitude of the back-wall reflection. While adequate for accepting or rejecting thin composite panels, this approach does not provide the level of defect characterisation and localisation necessary for the quantitative NDE of larger components.There is a clear and pressing industrial need for quantitative NDE techniques that can be applied to safety-critical composite components both at manufacture and in-service. An ultrasonic technique is the industrially preferred option for reasons of cost, safety and ease of deployment, but increased scanning speeds are required to speed up throughput. However, the conflicting demands of rapid scanning, high-penetration depth and accurate defect characterisation cannot be achieved with a single normal-incidence probe. Instead the data from multiple inspection directions must be combined. The necessary raw data can be rapidly and efficiently obtained using an ultrasonic array, but at present it cannot be exploited. This is due to the lack of (a) an appropriate forward model of oblique wave propagation and scattering processes, and (b) a suitable inversion scheme to turn the raw data into useful information. This is the motivation for the proposed research programme, the aim of which is to develop ultrasonic array data processing techniques based on physical reasoning for the characterisation of safety-critical aerospace composites. The programme requires advancement of the fundamental science of wave phenomena in composites, the solution of a challenging inverse problem and, crucially, the translation of the scientific findings into practical industrial solutions.

The purpose of the Manufacturing Technology Centre (MTC) Engineering Doctorate Centre is to accelerate the adoption and utilisation of new high-value manufacturing technologies within UK industry by bridging the identified gap between basic research and technology commercialisation in this area. This will be achieved through partnership between university research partners (the University of Nottingham, Loughborough University and the University of Birmingham) and founding MTC industrial members (Rolls-Royce, Airbus, Aero Engine Controls) through co-sponsorship and co-supervision of cohorts of Engineering Doctorate Research Engineers to tackle key research challenges in Net Shape Manufacturing, Advanced Tooling and Fixturing and Intelligent Automation. The 12,000 sqm purpose-built 25M MTC building at Ansty, Warwickshire will provide a hub for the researchers, who will benefit from investment in large-scale research equipment and access to key research and technical staff. Research Engineers will benefit from a carefully constructed formal training programme combining advanced technical skills with management/professional development training and contextual awareness. This is to ensure that Research Engineers are not only equipped with detailed hands-on knowledge of the latest advanced manufacturing methods and approaches but also an understanding of how their research fits within the value chain so as to achieve optimal solutions.

Given the unprecedented demand for mobile capacity beyond that available from the RF spectrum, it is natural to consider the infrared and visible light spectrum for future terrestrial wireless systems. Wireless systems using these parts of the electromagnetic spectrum could be classified as nmWave wireless communications system in relation to mmWave radio systems and both are being standardised in current 5G systems. TOWS, therefore, will provide a technically logical pathway to ensure that wireless systems are future-proof and that they can deliver the capacities that future data intensive services such as high definition (HD) video streaming, augmented reality, virtual reality and mixed reality will demand. Light based wireless communication systems will not be in competition with RF communications, but instead these systems follow a trend that has been witnessed in cellular communications over the last 30 years. Light based wireless communications simply adds new capacity - the available spectrum is 2600 times the RF spectrum. 6G and beyond promise increased wireless capacity to accommodate this growth in traffic in an increasingly congested spectrum, however action is required now to ensure UK leadership of the fast moving 6G field. Optical wireless (OW) opens new spectral bands with a bandwidth exceeding 540 THz using simple sources and detectors and can be simpler than cellular and WiFi with a significantly larger spectrum. It is the best choice of spectrum beyond millimetre waves, where unlike the THz spectrum (the other possible choice), OW avoids complex sources and detectors and has good indoor channel conditions. Optical signals, when used indoors, are confined to the environment in which they originate, which offers added security at the physical layer and the ability to re-use wavelengths in adjacent rooms, thus radically increasing capacity. Our vision is to develop and experimentally demonstrate multiuser Terabit/s optical wireless systems that offer capacities at least two orders of magnitude higher than the current planned 5G optical and radio wireless systems, with a roadmap to wireless systems that can offer up to four orders of magnitude higher capacity. There are four features of the proposed system which make possible such unprecedented capacities to enable this disruptive advance. Firstly, unlike visible light communications (VLC), we will exploit the infrared spectrum, this providing a solution to the light dimming problem associated with VLC, eliminating uplink VLC glare and thus supporting bidirectional communications. Secondly, to make possible much greater transmission capacities and multi-user, multi-cell operation, we will introduce a new type of LED-like steerable laser diode array, which does not suffer from the speckle impairments of conventional laser diodes while ensuring ultrahigh speed performance. Thirdly, with the added capacity, we will develop native OW multi-user systems to share the resources, these being adaptively directional to allow full coverage with reduced user and inter-cell interference and finally incorporate RF systems to allow seamless transition and facilitate overall network control, in essence to introduce software defined radio to optical wireless. This means that OW multi-user systems can readily be designed to allow very high aggregate capacities as beams can be controlled in a compact manner. We will develop advanced inter-cell coding and handover for our optical multi-user systems, this also allowing seamless handover with radio systems when required such as for resilience. We believe that this work, though challenging, is feasible as it will leverage existing skills and research within the consortium, which includes excellence in OW link design, advanced coding and modulation, optimised algorithms for front-haul and back-haul networking, expertise in surface emitting laser design and single photon avalanche detectors for ultra-sensitive detection.