[EnAble]: Developing and Exploiting Intelligent Approaches for Turbulent Drag Reduction

Whenever air flows over a commercial aircraft or a high-speed train, a thin layer of turbulence is generated close to the surface of the vehicle. This region of so-called wall-turbulence generates a resistive force known as skin-friction drag which is responsible for more than half of the vehicle's energy consumption. Taming the turbulence in this region reduces the skin-friction drag force, which in turn reduces the vehicle's energy consumption and thereby reduces transport emissions, leading to economic savings and wider health and environmental benefits through improved air quality. To place this into context, just a 3% reduction in the turbulent skin-friction drag force experienced by a single long-range commercial aircraft would save £1.2M in jet fuel per aircraft per year and prevent the annual release of 3,000 tonnes of carbon dioxide. There are currently around 23,600 aircraft in active service around the world. Active wall-turbulence control is seen as a key upstream technology currently at very low technology readiness level that has the potential to deliver a step change in vehicle performance. Yet despite this significance and well over 50 years of research, the complexity of wall-turbulence has prevented the realisation of any functional and economical fluid-flow control strategies which can reduce the turbulent skin-friction drag forces of industrial air flows of interest.

The EnAble project aims to develop, implement and exploit machine intelligence paradigms to enable a new approach to wall-turbulence control. This new form of intelligent fluid-flow control will be used to develop practical wall-turbulence control strategies that can rapidly and autonomously optimise the aerodynamic surface with minimal power input whilst being adaptive to changes in flow speed. This new capability will open up the opportunity to discover new ways to tame wall-turbulence and exploit the latest drag reduction mechanisms to generate significant levels of turbulent skin-friction drag reduction.

The key to reducing carbon dioxide (CO2) emissions across the global transportation network resides in developing technology which lowers fuel consumption. Net-energy savings by reducing the skin-friction drag force by only a few percent would create a more energy efficient global transportation network. This would lead to vast economic savings and improved air quality, which in turn would lead to an increase in health and quality of life. Net-energy saving approaches are particularly pertinent at present given our government's recent lawful pledge (June 2019) to be a net-zero carbon emission economy by 2050, marking the UK as being the first member of the G7 group to legislate net-zero emissions, resulting in an amendment to the Climate Change Act: https://www.theguardian.com/theresa-may-commits-to-net-zero-uk-carbon-emissions-by-2050. The EnAble project aims to help transition the UK towards being this low-carbon economy. Noting the growing interest in battery technology and the production of green energy, alternatively powering an active low-powered control solution, rather than relying on the usual fossil fueled systems, could yield significant savings in transport emissions ahead of any full-scale alternative-energy revolution. More broadly, energy reduction in any system can only be positive. The EnAble project will develop fundamental underpinning technology in consultation with Airbus and the Aerospace Technology Institute (ATI) to provide pathways to future industrial uptake of our research.

The development of the EnAble project's new machine intelligence technology is very "media-friendly" as it ultimately targets mitigating global climate change and is therefore likely to capture the imagination of the public. To capitalise on this, the EnAble team will take full advantage of the Imperial College Media Team and Newcastle University's Press Office who will support the development of short video clips to promote the project's research outputs via the BBC, Talks for Schools Programme, Reach Out Reporter and ReachOut CPD and STEM outreach for Schools and Colleges. In addition, the EnAble project will dedicate funds to train the PDRAs in public engagement skills via a 2-day course with the Royal Society. The team will use this training to engage with the general public at Science cafes around the UK, such as Café Culture North East, as well as during the Imperial Festival and Imperial Fringe events, and with young adults during the Science and Technology Facilities Council's yearly open week.

The EnAble team will open the source code of Incompact3d (the flow solver which forms a cornerstone of the EnAble project) and the developed machine intelligence tools to the scientific community via a dedicated website. EnAble's Advisory Board will play a key role in developing pathways to impact. Professor Phil Blythe, the Chief Scientific Advisor for the Department for Transport, and Chair of Intelligent Transport Systems at Newcastle University will provide a vital link to UK government where the research from the EnAble project may ultimately help to inform UK government policy on transport, energy and climate change. Dr Stuart Gates, the Aerospace Technology Institute's lead technologist and the institute's specialist for aerodynamics, and focal point for industry and academia will provide a pivotal role in enabling the team to disseminate research findings to stakeholders across the UK aerospace sector. Further, Dr Stephen Rolston, Head of Aeromechanics at Airbus UK, will provide an important link directly back into the UK aerospace industry to ensure every possibility that EnAble's research findings can be further developed and fully exploited by the UK aerospace sector.