Optimisation problems appear across all areas of engineering. Optimisation consists of maximising the performance or minimising the cost of a system, subject to some constraints. For example, an aeronautical engineer will want to choose the best shape for a wing to maximise its efficiency, subject to the constraint that the wing will lift the aircraft, while a civil engineer will want to design the cheapest bridge that will support its load. An important class of optimisation problems is where the constraint is given by the laws of physics, such as the physical laws for fluids (in the wing case) and structures (in the bridge case). These problems can be very hard, and usually require massive supercomputers to solve them. A significant amount of mathematical research has gone into investigating techniques for solving them. Engineers currently face a major practical difficulty when trying to solve new kinds of such optimisation problems. The software required to solve these is very intricate, and often takes months or years to develop. This poses a very formidable barrier. This matters a lot, because these problems appear everywhere in engineering, and if we could solve them then we could design many things in a better way. I propose to do this by developing a software framework to generate optimisation codes, rather than have engineers develop them by hand. While the optimisation software is very complex, it has a compact mathematical structure: I propose to generate the optimisation software from a simple high-level description of this mathematical structure. By generating the necessary software, engineers can spend their time on using it to solve real problems. This framework will provide engineers with the necessary optimisaton software in days or weeks instead of months or years. Generating the optimisation codes from simple high-level input has another major advantage. The high-performance supercomputers necessary to solve these optimisation problems are extremely difficult to program efficiently, and are changing rapidly. Code must be tailored for a particular hardware architecture. As each new kind of computing platform comes out, an engineer must adapt the code. Instead, with my new approach, the engineer can simply re-generate the code from the same mathematical input, and the framework will specialise the code to best exploit the different platform. By updating the framework once, many engineers working on many different codes in many different areas can benefit quickly from advances in computational hardware. I will apply the software developed to two important engineering problems. The first engineering problem is found in the design of marine turbine farms for renewable energy. Marine renewable energy is very important to the UK. The government predicts that the industry will be worth £76 billion to the UK economy by 2050. A major problem facing the industry is how to position the turbines to extract the maximum possible energy from the tide. Choosing the best design is very important, as it can greatly change the efficiency. Solving this problem will directly contribute to the UK's energy security and carbon reduction goals. The second engineering problem is identifying regions of the heart that are damaged (ischaemic). Ischaemic heart disease is the most common cause of death in Western countries. When a doctor suspects that a patient has ischaemia, it would be very beneficial to know its location and extent. One possible approach to rapidly identify ischaemia is to extract information from electrocardiograms (ECGs). The optimisation problem is to identify the ischaemia that best explains the ECG measured from the patient. Solving this problem will directly contribute to better healthcare decisions, reducing the mortality rate and improving the long-term prognosis of survivors.

The coastal zone plays a crucial part in addressing two of the most pressing issues facing humanity: energy supply and water resources. Marine renewable energy and desalination are both characterised by the deployment of relatively small-scale technology (for example, tidal turbines, or desalination plant outfalls) in large-scale ocean flows. Understanding the multi-scale interactions between sub-metre scale installations and ocean currents over tens of kilometres is crucial for assessing environmental impacts, and for optimisation to minimise project costs or maximise profits. The vast range of scales and physical processes involved, and the need to optimise complex coupled systems, represent highly daunting software development and computational challenges. Geographically, the UK is uniquely positioned to become a world leader in marine renewable energy, but adequate software will be a key factor in determining the success of this new industry. To address this need, this project will re-engineer a unique CFD to marine scale modelling package to provide performance-portability, future-proofing and substantially increased capabilities. To motivate this we will target two applications: renewable energy generation via tidal turbine arrays and dense water discharge from desalination plants. Both are characterised by a common wide range of spatial and temporal scales, the need for design optimisation and accurate impact assessments, and a current lack of the required software. This project will build upon several world-leading open source software projects from the assembled multi-disciplinary research team. This team already has a long and successful track record of working together on the development of high quality open source software which is able to exploit large-scale high performance computing and has been used widely in academia and industry. In addition, the project has assembled a wide range of suitable project partners to aid in the delivery of the project as well as to promote longer term impact. These include complementary centres of excellence in cutting-edge software development, industry leaders in the targeted application areas, marine consultancies, and those contributing to environmental regulation.

The proposed new CCP-WSI+ builds on the impact generated by the Collaborative Computational Project in Wave Structure Interaction (CCP-WSI) and extends it to connect together previously separate communities in computational fluid dynamics (CFD) and computational structural mechanics (CSM). The new CCP-WSI+ collaboration builds on the NWT, will accelerate the development of Fully Coupled Wave Structure Interaction (FCWSI) modelling suitable for dealing with the latest challenges in offshore and coastal engineering. Since being established in 2015, CCP-WSI has provided strategic leadership for the WSI community, and has been successful in generating impact in: Strategy setting, Contributions to knowledge, and Strategic software development and support. The existing CCP-WSI network has identified priorities for WSI code development through industry focus group workshops; it has advanced understanding of the applicability and reliability of WSI through an internationally recognised Blind Test series; and supported collaborative code development. Acceleration of the offshore renewable energy sector and protection of coastal communities are strategic priorities for the UK and involve complex WSI challenges. Designers need computational tools that can deal with complex environmental load conditions and complex structures with confidence in their reliability and appropriate use. Computational tools are essential for design and assessment within these priority areas and there is a need for continued support of their development, appropriate utilisation and implementation to take advantage of recent advances in HPC architecture. Both the CFD and CSM communities have similar challenges in needing computationally efficient code development suitable for simulations of design cases of greater and greater complexity and scale. Many different codes are available commercially and are developed in academia, but there remains considerable uncertainty in the reliability of their use in different applications and of independent qualitative measures of the quality of a simulation. One of the novelties of this CCP is that in addition to considering the interface between fluids and structures from a computational perspective, we propose to bring together the two UK expert communities who are leading developments in those respective fields. The motivation is to develop FCWSI software, which couples the best in class CFD tools with the most recent innovations in computational solid mechanics. Due to the complexity of both fields, this would not be achievable without interdisciplinary collaboration and co-design of FCWSI software. The CCP-WSI+ will bring the CFD and CSM communities together through a series of networking events and industry workshops designed to share good practice and exchange advances across disciplines and to develop the roadmap for the next generation of FCWSI tools. Training and workshops will support the co-creation of code coupling methodologies and libraries to support the range of CFD codes used in an open source environment for community use and to aid parallel implementation. The CCP-WSI+ will carry out a software audit on WSI codes and the data repository and website will be extended and enhanced with database visualisation and archiving to allow for contributions from the expanded community. Code developments will be supported through provision and management of the code repository, user support and training in software engineering and best practice for coupling and parallelisation. By bringing together two communities of researchers who are independently investigating new computational methods for fluids and structures, we believe we will be able to co-design the next generation of FCWSI tools with realism both in the flow physics and the structural response, and in this way, will unlock new complex applications in ocean and coastal engineering