4 year scholarship: year 1 PG Dip; year 2 PhD. PhD title: Quantifying Enhanced Mixing of Stratified Shelf Seas by Offshore Wind Infrastructure

Despite its importance to many geophysical systems, including the atmosphere and the world's oceans, there remain significant open challenges to our fundamental understanding of turbulent stratified flows. Whilst offshore wind developments to-date have predominately been constructed in well-mixed unstratified coastal waters, growth of the offshore wind sector now requires the first ever large-scale industrialisation of stratified shelf seas. Sector growth and development in these new environments is necessary to meet the UK's 2050 net zero carbon commitments, yet the impact of offshore wind infrastructure, a source of anthropogenic mixing to stratified shelf seas, has not yet been quantified.

Stratification is a critical system control in shelf seas. Vertical density variations act to suppress vertical transport of energy, nutrients, CO2, heat, salinity, and sediment. Stratification is therefore crucial to both the physics and ecosystems of shelf seas, and the potential impact of anthropogenic mixing is significant. In addition, turbulent mixing of flow past infrastructure imposes constant drag forces on foundations which will vary in stratified waters. Understanding the impact of stratification on mixing from, and hydrodynamic loading of, offshore renewable energy structures is needed to inform Environmental Impact Assessments as well as future fixed and floating platform designs. It is vital that environment-engineering based solutions are developed now to enable sustainable and rapid large-scale expansion of offshore renewable energy into stratified shelf seas.

New understanding of turbulent mixing in stratified flow past infrastructure is required to aid both future design and to quantify environmental impact, from single turbine to array scale. To address these challenges the successful candidate will develop local scale oceanographic computational fluid dynamic models of turbulent mixing in offshore windfarms. Models will be used to quantify environmental impact, and imposed loads from stratified flow past different infrastructure.

This PhD will address three key research questions:

How does wind turbine infrastructure affect density stratification and material transport?
What role does density stratification have on hydrodynamic loading of offshore wind infrastructure?
Can the influence of offshore wind infrastructure on density stratification be mitigated against through novel foundation design?


Methodology: Numerical Investigation
In collaboration with ORE Catapult. No ethical issues.

The Aura CDT will produce offshore wind specialists with a multi-disciplinary perspective, and will equip them with key skills that are essential to meet the future sector challenges. They will be highly employable due to their training being embedded in real-world challenges with the potential to become future leaders. As such, they will drive the UK forward in offshore wind development and manufacturing. They will become ambassadors for cross-disciplinary thinking in renewables and mentors to their colleagues. With its strong industrial partnership, this CDT is ideally placed to produce high impact research papers, patents and spin-outs, with support from the Universities' dedicated business development teams. All of this will contribute to the continued strong growth of the offshore wind sector in the UK, creating more jobs and added value to the UK economy. Recent estimates suggest that, to meet national energy targets, developers need >4,000 offshore wind turbines, worth £120 billion, over the next decade.

Alongside the clear benefits to the economy, this CDT will sustain and enhance the UK as a hub of expertise in this rapidly increasing area. The UK has made crucial commitments to develop low carbon energy by 2050 and this will require an estimated ~£400m UK RDI spend per year by 2032. Whilst the increase in R&D is welcome, this target will be unsustainable without the right people to support the development of alternative technologies. It is estimated that 27,000 skilled jobs, including in research, will need to be generated in the OSW sector. Of these, ~2,000 are estimated to require HE Level 7-8 qualifications. This CDT will directly answer the higher-level leadership skills shortage, enabling the UK to not only meet these targets but lead the way internationally in the renewables revolution.

Industry and policy stakeholders will benefit through-
a) Providing challenges for the students to work through which will result in solutions to pressing and long-term industry challenges
b) Knowledge exchange with the students and the academics
c) New lines of investigation/ revenue/ process improvement
d) Two-way access to skills/ equipment and training
e) A skilled, challenge focused workforce
Society will benefit through-
a) Offshore wind energy that is lower cost, more secure and more environmentally friendly, with a lower impact on precious marine eco-systems.
b) Engineers with new skillsets and perspectives that can understand environmental constraints
c) Skilled workforce who are mindful of the environmental and ethical impact
d) Graduates that understand and value equality, diversity and inclusion

The research projects undertaken by the Aura CDT students will focus on projects with a strong impact. The 6 themes have all been chosen after extensive industrial consultation and engagement that accelerated after the formation of the wider Aura initiative in 2016. The collaborative approach which has shaped this proposal will be continued and enhanced through the life of the CDT to ensure that it remains aligned to industry priorities.

The interdisciplinary nature of the OSW industry means that there are a wide range of stakeholders including large and small companies who are active at different stages of OSW farm development. These industry players will help ensure the training and experience provided in the CDT addresses the range of challenges that the industry faces.