Microprocessors chips are in most devices we interact with in our daily lives. From mobile devices, TVs, cars, fridges, petrol station pumps, servers that power the web and social media infrastructure --- the list is endless. Microprocessors have been doubling in power roughly every two years following Moore's law, which has been enabled by making the features of the chips smaller, fitting more transistors per unit area and driving the entire consumer electronics market worth more than £1 trillion per year. In order to continue to satisfy the industrial and societal demand that drives Moore's law, there are some fluid dynamics modelling challenges that we need to overcome. The next-generation of photolithography machines that need to manufacture smaller, faster microprocessor chips and the new devices required to supercool the high-performance chips during operation can be enabled by understanding and predicting accurately how gases behave at the micro/nanoscales, or in vacuum-like conditions. In these multiscale flow problems, the fluid dynamics is often unintuitive and all equations we normally turn to for modelling and designing engineering flow problems, such as flow around aircraft and ships using Navier-Stokes equations, are no longer valid here, because the gas is no longer in local thermodynamic equilibrium, on which these classical equations are formulated. The direct simulation Monte Carlo (DSMC), is the state-of-the-art software for modelling these non-equilibrium gas flows. It is a stochastic particle method with large numerical stability and can resolve the molecular nature of gases in three dimensional geometries. However, because it is a particle method, it requires a voracious computational cost to produce engineering solutions of scales that matter to industry. DSMC also performs poorly if those flows are at low speed, due to the inherent thermal noise in the particles blocking the measurable signals. In this project, we propose developing a new multiscale method, one which combines DSMC with computationally cheaper models such as those used in Computational Fluid Dynamics (CFD). We will produce a step change in simulation efficiency and accuracy by connecting DSMC and CFD solvers using surrogate modelling and Bayesian inference. With strong backing from our industrial partners, we will turn the outcome of this project into a free open-source computational solver released in the UK's OpenFOAM software that is validated with experimental data. The industrial focus of this project will be on processor-chip manufacturing, chip thermal management and electrospray technologies, but the underlying method is general to new directions in other research and industrial areas.

The High End Computing Consortium for Wave Structure Interaction (HEC WSI) is a new and emerging communities consortium that represents the established community of researchers in wave structure interaction that are working together through the support of the CCP-WSI+ (Collaborative Computational Project on Wave Structure Interaction plus). This brings together a community of researchers in computational fluid dynamics (CFD) and computational structure mechanics (CSM) who are developing and applying fully coupled wave structure interaction numerical modelling tools suitable for the latest challenges in coastal and ocean engineering, and other wave structure interaction (WSI) free surface flow problems, such as sloshing in containers and liquid fuels, and would benefit from access to significant HPC resource. The consortium addresses underpinning research applicable to Net Zero and Decarbonisation solutions aligned with UK Government strategy and will enable new science and innovation unlocked by access to high-end computing capabilities for solving WSI problems in these areas. The consortium will make significant technical developments of software codes to enhance their suitability for high-end computing. These will include optimising key codes used within the WSI community to achieve better scalability of the multi-phase solvers, developing tools to allow interoperability between the solvers for fluids and solid mechanics, developing coupling strategies between wave, wind, rigid body and hydro elastics models for different applications in costal/ocean engineering and related areas, and also developing AI/ML surrogate modelling tools informed by high fidelity WSI simulations utilising the aforementioned developments. The consortium will maximise the involvement of the whole community working on coastal and ocean engineering and related areas. These will include providing the opportunity for researchers in the community to port and benchmark their own codes and to use the software codes supported by the consortium on the HPC resource. The HEC WSI will also provide opportunities for early career researchers to learn and become proficient in using HPC resources and will serve as a forum to communicate research and share HEC WSI expertise within the WSI community, helping to promote the highest quality engineering research and provide leadership in developing strategic agendas for the WSI community. The success of this consortium will be ensured by supporting the existing wide CCP-WSI+ network of over 200 researchers, spanning academia and industry in 5 continents working on WSI, ORE (offshore renewable energy) and other relevant applications and sectors. The community will be strengthened and consolidated through this project. The HEC WSI will expand the volume of users, provide support for the WSI and wider community and significantly enhance WSI codes for them to be used on HPCs and most advanced high-end computing systems by the end of this project.