3D modelling of subsea jet trenching and its sediment plume impacts

Description

The EPSRC Centre for Doctoral Training in Net Zero Maritime Energy solutions (N0MES) has a 4-year funded PhD place available for an exceptional researcher. With the support of the University of Liverpool (UoL), Liverpool John Moores University (LJMU) and 33 maritime energy sector partners, N0MES PGRs will pursue new, engineering-centred, interdisciplinary research to address four vital net zero challenges currently facing the North West, the UK and beyond:

a) Energy generation using maritime-based renewable energy (e.g. offshore wind, tidal, wave, floating solar, hydrogen, CCS);

b) Distributing energy from offshore to onshore, including port- and hinterland-side impacts and opportunities;

c) Addressing the short- and long-term environmental impacts of offshore and maritime

environment renewable energy generation, distribution and storage; and

d) Decommissioning and lifetime extension of existing energy and facilities.

Offshore renewable energy including wind, solar, tidal and wave is considered a key enabler to achieve the Net Zero target in the UK and EU by 2050. Cables are key elements in this system to bring the power ashore. To avoid damage and minimize impacts from the marine activities such as fishing and environmental hazards like marine landslide, the submarine electrical cables are usually buried in trenches beneath the seabed. Water jet trenching is widely used for burying cables and pipelines. The design of the jet nozzle is heavily relied on empirical formula based on limited experimental tests and simple soil failure theory without sufficient understanding of the sediment movement process. The knowledge gap hinders effective design of jet nozzles to fluidize the soil and power allocation for maintaining the sediment in suspension to avoid backfilling which reduces the design trenching depth. On the other hand, the trenching activity generates sediment plum above the seabed which may have regional environmental impact based on the concentrations of sediment in suspension and the thickness of sediment re-deposited to the seafloor. To effectively assess those impacts it is of great important to quantify the source of the sediment initiated by the water jet in the trench.

The aim of the project is to simulate soil fluidization, suspension and deposition processes under high pressure water jet. Through systematic simulations covering a wide range of sediment properties, jet flow conditions and trencher speeds, results will provide guidance for nozzle design and quantify the sediment sources from the trench for regional plum impact assessment. The model will be developed based on the in-house SPH two-phase model.

Soil Machine Dynamics Limited (SMD) will provide supervisory support with Chief Engineer Roger White acting as the co-supervisor. They will also provide lab tests and sea test data for small- and full-scale model validation respectively. Short term placement in SMD is also available.

We want all of our staff and Students to feel that Liverpool is an inclusive and welcoming environment that actively celebrates and encourages diversity. We are committed to working with students to make all reasonable project adaptations including supporting those with caring responsibilities, disabilities or other personal circumstances. For example, If you have a disability you may be entitled to a Disabled Students Allowance on top of your studentship to help cover the costs of any additional support that a person studying for a doctorate might need as a result.

We believe everyone deserves an excellent education and encourage students from all backgrounds and personal circumstances to apply.

Applicant Eligibility

Candidates will have, or be due to obtain, a Master’s Degree or equivalent from a reputable University in an appropriate field of Engineering. Exceptional candidates with a First Class Bachelor’s Degree in an appropriate field will also be considered.

Application Process

Candidates wishing to apply should complete the University of Liverpool application form [How to apply for a PhD - University of Liverpool] applying for a PhD in Civil Engineering and uploading: Degree Certificates & Transcripts, an up-to-date CV, two academic references and a supporting statement [maximum 300 words] detailing; what inspires you within this project, how your skill set matches the project, up to 3 examples showing your commitment so science, piece of science that excites you & anything else to support your application.

Candidates wishing to discuss the research project should contact the primary supervisor yanzhou@liverpool.ac.uk, those wishing to discuss the application process should discuss this with the CDT Manager Matt Fulton [n0mescdt@liverpool.ac.uk].