Concrete is one of the most widely used materials in the world. For many years traditional processes have been used to make concrete parts. However, over the last decade, 3D printing has revolutionised the way concrete parts are made. Complex concrete parts can now be created with no formwork or mould tooling. This is important as it removes the time and expense associated with making the moulds, but critically it also offers the potential to create parts that are structurally optimised to maintain strength with less material. This brings benefits in terms of cost but also it represents a significant environmental benefit as less material is needed, so carbon dioxide equivalent emissions are also reduced. The process is still in development though, and current 3D printing processes result in geometric forms and surface finishes that are not always desirable, and part accuracy that is too low for many applications. To address this, the 3D printing process can be followed immediately by a subtractive process that mills the surface to trim off unwanted material. This improves both accuracy and surface finish. By using a two-stage process of deposition followed by milling, it is possible to create high-quality parts, with intricate features and well-controlled surface finishes. The problem is that for each new part manufactured in this way, many iterative process development trials are required to perfect the deposition and milling strategy. This is time-consuming and wasteful, and it is a barrier to the uptake of the technology. The First Time Concrete (FT-Concrete) project will address this problem by creating new digital process and material models that can be used to help design printing and milling strategies without the need for physical trials. To do this, these models will be coupled within a digital workflow that enables optimised process design of both the material deposition and the milling process together. So, for a given part the feasibility of defect free manufacturing can be assessed, and the part or process design can be optimised, to ensure parts are printed right first time. This will be a two-way process, where printing sequence, speed and geometry will be optimised to suit milling requirements and vice versa. To achieve this the FT-Concrete project will investigate new time-dependent material properties models that can predict the curing state and optimal milling window and milling parameters for every position in a part. These must account for the variability of the mix, ambient conditions, printing sequence and the shape of the printed parts. New complementary process models for milling 3D printed concrete in a 'green' state will also be created. These must be able to cope with the highly variable material properties inherent to curing concrete. Finally, these new models will be integrated within a digital design system that will reduce, or potentially remove, the need for physical prototype parts. The new digital process and material models that we envisage, together with a digitally coupled design process will have significant commercial value; as they have the potentially to reduce process development time, material waste, and cost. We believe this could unlock 3D concrete printing to a wide range of new applications, boosting the uptake of the technology. Enabling structures and geometries that are currently impossible to produce. To pave the way for the uptake of these models, our aim is to integrate them within freely available, opensource, 3D printing design software. In addition, we will work with industrial partners to demonstrate the potential of the digital approach through industrially driven case studies.

The construction sector is strategically important to the UK economy, employing 3.1 million people (>9% of the workforce), producing £370 billion in turnover, and exporting more than £8 billion in products and services. However, its current philosophy is resource and cost inefficient and environmentally unsustainable, through its low productivity, slow technology adoption and tendency to demolish and rebuild. Metal 3D printing offers opportunities to solve these challenges and lead to a more productive, innovative and sustainable construction sector. Metal 3D printing technology has transformed other engineering disciplines, including the biomedical and aeronautical sectors, while its application within the construction sector is still in its infancy. The technology has been fundamentally proven through the MX3D Bridge, the first metal 3D printed structure that was opened in July 2021, however there are still a number of barriers preventing more widespread adoption. Current equipment and processes produce elements that have significant material and geometric variability, within the same build and between repeated builds, which is not optimal for real-world use. Furthermore, the limited availability of suitable printing equipment has prevented research into the development of this novel manufacturing technique and its applications to the construction sector. ICWAAM will be a globally unique metal 3D printing facility, dedicated to large-scale, cost-effective applications for the construction sector. It will offer new research capabilities into the printing process, automated manufacture and the repair and upgrade of our critical infrastructure, along with the printing of complex, materially efficient geometries, which are uneconomical or impossible with standard techniques. ICWAAM will fundamentally challenge the current philosophy of the construction industry and lead to its transformation into a more productive, innovative and sustainable sector, with increased worker safety. Without direct access to large-scale metal 3D printing equipment, such as ICWAAM, researchers are unable to undertake this critical research and development, to solve the longstanding challenges in the construction sector.

Schools are planning to re-open in September and with the recent increased awareness of airborne transmission of Covid-19, there is an urgent need to monitor the situation and to provide guidance on ventilation best practice. This is emphasised by the expected onset of cooler weather when there will be a conflict between maintaining high fresh air ventilation flows and energy consumption and occupant comfort. We will quantify the risk of airborne COVID-19 transmission in schools and evaluate the effectiveness of mitigation measures, by developing techniques to assess the absolute risk of infection in a given indoor space, using field studies in primary and secondary schools, complemented by laboratory experiments and CFD to elucidate the flow patterns responsible for airborne transport. The understanding generated will underpin recent developments in infection modelling to predict the likelihood of airborne transmission within schools. The project will reduce the uncertainties associated with airborne transmission routes and provide evidence to evaluate mitigation measures. The scenarios we will investigate include changes to ventilation, use of screens, classroom lay-out and occupancy profiles. The methodology will facilitate application to offices, restaurants, shops etc. Airborne infection occurs through re-breathed air, the concentration of which can be directly inferred from measurements of CO2. Indoor flow is strongly affected by the locations of windows or vents, the heat rising from occupants/equipment and disturbances caused by people movement. Thus, accurate representations of these processes in the laboratory and CFD are needed to interpret the monitoring data currently collected in schools, which are typically single point measurements.

This proposal brings together communities from the UK Turbulence Consortium (UKTC) and the UK Consortium on Reacting Flows (UKCRF) to ensure a smooth transition to exascale computing, with the aim to develop transformative techniques for future-proofing their production simulation software ecosystems dedicated to the study of turbulent flows. Understanding, predicting and controlling turbulent flows is of central importance and a limiting factor to a vast range of industries. Many of the environmental and energy-related issues we face today cannot possibly be tackled without a better understanding of turbulence. The UK is preparing for the exascale era through the ExCALIBUR programme to develop exascale-ready algorithms and software. Based on the findings from the Design and Development Working Group (DDWG) on turbulence at the exascale, this project is bringing together communities representing two of the seven UK HEC Consortia, the UKTC and the UKCTRF, to re-engineer or extend the capabilities of four of their production and research flow solvers for exascale computing: XCOMPACT3D, OPENSBLI, UDALES and SENGA+. These open-source, well-established, community flow solvers are based on finite-difference methods on structured meshes and will be developed to meet the challenges associated with exascale computing while taking advantage of the significant opportunities afforded by exascale systems. A key aim of this project is to leverage the well-established Domain Specific Language (DLS) framework OPS and the 2DECOMP&FFT library to allow XCOMPACT3D, OPENSBLI, UDALES and SENGA+ to run on large-scale heterogeneous computers. OPS was developed in the UK in the last ten years and it targets applications on multi-block structured meshes. It can currently generate code using CUDA, OPENACC/OPENMP5.0, OPENCL, SYCL/ONEAPI, HIP and their combinations with MPI. The OPS DSLs' capabilities will be extended in this project, specifically its code-generation tool-chain for robust, fail-safe parallel code generation. A related strand of work will use the 2DECOMP&FFT a Fortran-based library based on a 2D domain decomposition for spatially implicit numerical algorithms on monobloc structured meshes. The library includes a highly scalable and efficient interface to perform Fast Fourier Transforms (FFTs) and relies on MPI providing a user-friendly programming interface that hides communication details from application developers. 2DECOMP&FFT will be completely redesigned for a use on heterogeneous supercomputers (CPUs and GPUS from different vendors) using a hybrid strategy. The project will also combine exascale-ready coupling interfaces, UQ capabilities, I/O & visualisation tools to our flow solvers, as well as machine learning based algorithms, to address some of the key challenges and opportunities identified by the DDWG on turbulence at the exascale. This will be done in collaboration with several of the recently funded ExCALIBUR cross-cutting projects. The project will focus on four high-priority use cases (one for each solver), defined as high quality, high impact research made possible by a step-change in simulation performance. The use cases will focus on wind energy, green aviation, air quality and net-zero combustion. Exascale computing will be a game changer in these areas and will contribute to make the UK a greener nation (The UK commits to net zero carbon emissions by 2050). The use cases will be used to demonstrate the potential of the re-designed flow solvers based on OPS and 2DECOMP&FFT, for a wide range of hardware and parallel paradigms.