Parameterising wakes for oceanographic models

This PhD scholarship is offered by the EPSRC CDT in Offshore Wind Energy Sustainability and Resilience; a partnership between the Universities of Durham, Hull, Loughborough and Sheffield. This project is supported by Centre for Environment, Fisheries and Aquaculture Science (CEFAS) and The National Oceanography Centre (NOC) . The successful applicant will undertake six-months of training with the rest of the CDT cohort at the University of Hull before continuing their PhD research at Loughborough University. The project is part of a PhD Research Cluster focusing on Predicting Offshore Wind wake interactions for Energy and the enviRonment (POWER).

The offshore wind sector is rapidly expanding to meet net-zero energy demands. Individual turbines and farms are getting larger and further from shore, with individual turbines spanning 240 m in diameter and farms reaching 600 km2. Forced by spatial constraints and enabled by floating technology, farms are now developing in deeper waters, occupying increasingly vast areas.

Oceanographic flow processes are highly sensitive to sea surface boundary conditions (Christiansen et al., 2022), which are in turn critically dependent on atmospheric forcing. Atmospheric flows past offshore wind turbines produce highly turbulent and extensive wakes. These wakes are a necessary result of energy extraction from the wind. They are a key motivation for spatial planning of offshore wind farms where turbine placement is optimised for maximum energy extraction while minimising costs associated with infrastructure and spatial footprint (Giebel et al., 2016). The turbulent wakes propagate downstream, leading to wake-wake interactions and farm-scale atmospheric flow processes with a significantly reduced wind speed in the lee of an offshore wind farm (Platis et al., 2018).

It has been recently shown that such large-scale atmospheric interactions can have a significant effect on sea-surface conditions, manifested through a locally reduced wind shear stress (Christiansen et al., 2022). Large-scale deployment of offshore wind farms in shelf seas therefore poses an emerging oceanographic problem; shelf seas are vital for life both on and below water through their control on the vertical transport of nutrients, and their role as a key component of the biogeochemical cycle (van Berkel et al., 2020). These are crucially dependent on general circulation and water column structure, which are both highly sensitive to conditions at the sea surface (Dorrell et al., 2022). Yet the impact of offshore wind expansion on sea surface conditions and subsequent regional scale effects is poorly understood and has only recently gained research interest. While wake parameterisations for atmospheric models have received significant interest over the last decade, the current state-of-the-art oceanographic models make sweeping assumptions regarding the form of sea-surface forcing, particularly concerning wake-wake interactions, spatial variability, and turbulent modifications (Christiansen et al., 2022). These limitations must be overcome for accurate prediction of oceanographic responses to offshore wind expansion.

This project aims to advance sea-surface parameterisations of atmospheric offshore wind farm wakes for use in oceanographic models, directly supported by the National Oceanography Centre, using the North-West European Shelf FVCOM model. This aim will be realised through the following objectives:

• Review literature and gather existing datasets required for model development and validation,
• Carry out simulations of atmospheric wind wakes using Computational Fluid Dynamics,
• Develop and validate sea-surface wind turbine wake parameterisations,
• Explore the potential impacts of current and future offshore wind development on North Sea oceanography, using FVCOM.

Completion of these objectives will deliver a functional oceanographic model for future research into impacts of offshore wind deployment to inform marine spatial planning.

Training & Skills

You will benefit from a taught programme, giving you a broad understanding of the breadth and depth of current and emerging offshore wind sector needs. This begins with an intensive six-month programme at the University of Hull for the new student intake, drawing on the expertise and facilities of all four academic partners. It is supplemented by Continuing Professional Development (CPD), which is embedded throughout your 4-year research scholarship.

You will undertake two three-week placements at NOC during the PhD programme to provide support with FVCOM. The first placement will occur at the start of year 2 where the basics of FVCOM will be taught. The second placement will occur at the start of year 3 to learn how to set up and validate FVCOM simulations, and implement parameterisations. Additional placement opportunities will be available with the physical oceanography team at CEFAS, to further embed PhD work within industry. Beyond academia, this PhD project will open pathways to a career in physical oceanography, the wind energy sector, or more broadly a career using computational fluid dynamics or data science.

Entry requirements

If you have received a First-class Honours degree, or a 2:1 Honours degree and a Masters, or a Distinction at Masters level with any undergraduate degree (or the international equivalents) in engineering, environmental science, mathematics and statistics or physics, we would like to hear from you. The ideal candidate for this project will have studied fluid mechanics/physical oceanography to a high level as part of their undergraduate degree.

Guaranteed interview scheme 

The CDT is committed to generating a diverse and inclusive training programme and is looking to attract applicants from all backgrounds. We offer a Guaranteed Interview Scheme for home fee status candidates who identify as Black or Black mixed or Asian or Asian mixed if they meet the programme entry requirements. This positive action is to support recruitment of these under-represented ethnic groups to our programme and is an opt in process. Find out more.

How to apply

Applications to the EPSRC CDT in Offshore Wind Energy Sustainability and Resilience are made to the University where the PhD project is based. You will find full instructions and links on the CDT website.