Wake induced mixing of stratified seas by offshore wind infrastructure

Research projects

  • Research area

    Physics and Engineering of the offshore environment

  • Institution

    University of Hull

  • Research project

    Wake induced mixing of stratified seas by offshore wind infrastructure

  • Lead supervisor

    Dr Charlie Lloyd (Leverhulme Early Career Research Fellow, Energy and Environment Institute, University of Hull)

  • PhD Student

    Open to new applicants

  • Supervisory Team

    Dr Stuart McLelland (Deputy Director of the Energy and Environment Institute, University of Hull, University of Hull)
    Dr Robert M Dorrell (Research Fellow – Faculty of Science and Engineering, University of Hull)
    Dr Magda Carr, Senior Lecturer in Applied Mathematics, Newcastle University
    David Hollis, LaVision

Project Description:

This PhD scholarship is offered by the Aura Centre for Doctoral Training in Offshore Wind Energy and the Environment; a partnership between the Universities of Durham, Hull, Newcastle and Sheffield. The successful applicant will undertake a PG-Dip training year and will continue their PhD research at University of Hull.

For more information visit www.auracdt.hull.ac.uk. Or if you have a direct question about the project, please email auracdt@hull.ac.uk and we will forward the query to the relevant supervisor. Please do not contact the project supervisors directly.

 

In the race for net zero the offshore wind sector is growing at an unprecedented rate; UK capacity will increase from 13GW current to 50 GW by 2030, then 140 GW by 2050. However, seafloor space is limited, and growth is now focused on deep waters facilitated by floating infrastructure technologies. Fundamentally different from the shallows of current operational sites, deeper waters are subject to seasonal stratification, where, in the spring-summer months, temperature and salinity gradients are a key control of mass, momentum, energy and nutrient transport through the water column. Stratified shelf seas are a vital part of marine ecosystems, controlling biological activity through primary production. The large-scale expansion of the offshore wind into deep-waters will have, currently unquantified, impacts on shelf sea physics and subsequent shelf sea functioning, due to the wakes shed flows past infrastructure.

There has been extensive research on turbulence generated by “bluff bodies” in unstratified (shallow) flows. In stratified flows strong buoyancy forces suppress turbulence and enable propagation of internal wave fields. However, despite profound potential impacts, the physics underpinning wakes shed by bluff bodies, such as wind turbine foundations, in stratified environments are only poorly understood.

The aim of this PhD is to address the open question: How do wakes shed by offshore wind infrastructure affect water column mixing, and how is mixing affected by infrastructure design? Working with industry leaders in flow imaging, the successful candidate will deliver this aim by:

  • Experimentally quantifying background mixing processes in a stratified shear flow and their dependence on governing flow parameters.
  • Experimentally investigating the mixing processes induced by scaled fixed-bottom offshore wind infrastructure wakes.
  • Experimentally investigating the mixing processes induced by scaled floating offshore wind infrastructure wakes.

These objectives will be achieved using a globally unique stratified flow facility at the University of Hull. Initial experiments will capture 3D datasets detailing base case flow processes dependent on vertical shear and temperature structure, analogous to stratified seas. Later experiments will investigate wakes and mixing behind 3D printed scale models of offshore wind infrastructure. With the unique opportunity to collaborate with, and benefit from, LaVision’s leading expertise in quantifying flow dynamics the successful candidate will develop a cutting edge suite of simultaneous and integrated optical measurement techniques, including: scanning Laser Induced Fluorescence (LIF); and tomographic Particle Tracking Velocimetry (PTV). The successful candidate will also be supported in use of state-of-the-art data processing techniques to identify, quantify, and visualise mixing processes in the stratified wakes generated by infrastructure.

The data gathered will provide some of the first empirical evidence of the additional mixing generated by offshore wind. Thus, the work of the successful candidate is urgently needed to motivate and benchmark environmental impact assessment modelling and foundation design for the immediate future of the sector.

 

Free Webinar

The University of Hull is running a webinar at 6pm on Tuesday 29 November to provide more information about the Aura CDT. The webinar will close with a Q&A giving you the opportunity to delve deeper into research opportunities, training provision and potential career paths. Book your place.

 

Entry requirements

If you have received a First-class Honours degree or a 2:1 Honours degree and a Masters (or the international equivalents) in Mathematics, Physics, Oceanography, Engineering or a closely related discipline we would like to hear from you. Some knowledge of fluid dynamics and an interest in experimental work are desirable.

If your first language is not English, or you require Tier 4 student visa to study, you will be required to provide evidence of your English language proficiency level that meets the requirements of the Aura CDT’s academic partners. This course requires academic IELTS 7.0 overall, with no less than 6.0 in each skill.

 

Funding

The Aura CDT is funded by the EPSRC and NERC, allowing us to provide scholarships that cover fees plus a stipend set at the UKRI nationally agreed rates, circa £17,668 per annum at 2022/23 rates (subject to progress).

Eligibility

Research Council funding for postgraduate research has residence requirements. Our Aura CDT scholarships are available to Home (UK) Students. To be considered a Home student, and therefore eligible for a full award, a student must have no restrictions on how long they can stay in the UK and have been ordinarily resident in the UK for at least 3 years prior to the start of the scholarship (with some further constraint regarding residence for education). For full eligibility information, please refer to the EPSRC website. In addition, a number of Aura CDT Scholarships will be available to International Students across the projects offered by the partner institutions.

 

How to apply

Applications are via the University of Hull online portal; you must also download a supplementary application form from the Aura CDT website, complete and submit as part of the online application.

For more information about the Aura CDT including links and detailed instructions please visit our how to apply page.

 

References:

Dorrell RM, Lloyd CJ, Lincoln BJ, Rippeth TP, Taylor JR, Caulfield CCP, Sharples J, Polton JA, Scannell BD, Greaves DM, Hall RA and Simpson JH (2022) Anthropogenic Mixing in Seasonally Stratified Shelf Seas by Offshore Wind Farm Infrastructure. Front. Mar. Sci. 9:830927. doi: 10.3389/fmars.2022.830927

Schultze, LKP, Merckelbach, LM, Horstmann, J, Raasch, S, & Carpenter, JR (2020). Increased mixing and turbulence in the wake of offshore wind farm foundations. Journal of Geophysical Research: Oceans, 125, e2019JC015858. https://doi.org/10.1029/2019JC015858

van Berkel, J, Burchard, H, Christensen, A, Mortensen, LO, Petersen, OS, & Thomsen, F (2020). The Effects of Offshore Wind Farms on Hydrodynamics and Implications for Fishes. Oceanography, 33(4), 108–117. https://www.jstor.org/stable/26965754

Join our free webinar on 29 November
for information on our 2023 PhD Scholarships

For enquiries, contact auracdt@hull.ac.uk