Bilateral wind flow interactions with floating offshore wind turbines

Project Description:

This funded PhD Research project is co-hosted by the EPSRC CDT in Offshore Wind Energy Sustainability and Resilience as part of the POWER (Predicting Offshore Wind wake interactions for Energy and the enviRonment) Cluster and by EDF Research & Development Departments.

Project Background:

This research project proposal specifically targets floating offshore wind energy, which is a developing market. As such, there are challenges and hurdles to overcome and uncertainties to deal with before widespread commercialisation and technological diffusion is realised. Conversely, this means there are plenty of opportunities for researchers and innovators to positively impact the growth trajectory of floating offshore wind.

Unlike fixed-bottom turbines, floating wind turbines are free to move along all 6 degrees of freedom (x, y, z translations, and roll, pitch, yaw rotations). This freedom of movement adds uncertainty when describing and modelling interactions between wind flows and turbines. Examples of wind energy applications known or expected to be affected by this added uncertainty include:

• Power performance testing/power curve validation
• Energy yield analysis
• Forecasting of power output
• Modelling of turbine wakes
• Modelling of induction zone and blockage effects
• Farm-farm flow interactions and cluster wakes.

Outputs of the above activities are subsequently subject to greater uncertainty, or contain more known and unknown errors and biases, relative to like exercises performed within fixed-bottom offshore wind. These uncertainties, errors and biases add cost, negatively affecting the competitiveness and viability of floating offshore wind technology.

This project represents an opportunity for novel research contributions to be made towards solving a problem set tangibly affecting the floating wind market today, with real potential for advancing the state of the art and for helping to shape industry consensus on modelling and describing wind flow interactions with floating wind turbines. The ask is for the research engineer to engage with as many affected wind energy applications as is practical and realistic, and to work towards identifying, quantifying and reducing uncertainties in the analytical outputs driven by controlled and uncontrolled motion of floating wind turbines.

The project scope and ambition is to be discussed and agreed with the successful student candidate. The focus could be on just one application, for example modelling of floating wind turbine wakes, or extended to gauging motion impacts on two or three applications. Possible applications cover a range of spatial and temporal scales and research areas, providing the student much choice amongst the software and modelling tools with which to conduct the research project. From a project planning perspective, it will therefore be important to strike the right balance between ambition and practicality.

EDF has wide ranging expertise on fluid-structure modelling and interactions spanning numerous departments across group level. There will be opportunities to connect and collaborate with group experts and knowledgeable persons from across the business who can offer technical guidance and direction, representing an additional rich source of support beyond that to be provided by the industrial supervisor. There could be also chance for the research engineer to spend time in different R&D departments (national and international) if there is interest from the student.

Additional benefits to being co-hosted by EDF R&D UKC:

• Lots of previous experience hosting doctorate students
• Currently the Renewables R&D team has 5 PhD students, including 2 embedded EngD students
• Flexibility and autonomy
• A friendly team and working environment
• Good links with other EDF business entities and departments including EDF R&D France (approx. 2000 researchers)
• Plentiful opportunities internally and externally for discussion and dissemination of academic and professional work. Support will be given to doctorate students wishing to leverage these opportunities.

Project objectives:

• Build in-depth knowledge and understanding of the ways in which wind flows interact bilaterally with floating offshore wind turbines. This could, for example, cover upstream, lateral and downstream flow-turbine interactions, across different floating wind farm configurations including a standalone turbine, pairs of turbines, single row of turbines, multiple rows of turbines up to clusters of wind farms.
• Recognition of the two-way (bilateral) nature of flow-FOWT interactions through consideration of the structural response of floating wind turbines to aerodynamic loadings. To consider secondary, knock-on effects of turbine responses and resultant flow perturbations on flow-structure interactions occurring at neighbouring turbines and turbines deeper within the array. To develop the expertise required to capture and represent these effects within models and methods.
• Conduct research on existing methods and models for describing two-way interactions between wind flow and floating turbines and build an excellent awareness of the literature available on the subject. To stay up to date with literature as the research project progresses.
• Participation within joint industry projects and to collaborative academic and cross-industrial research groups. Similarly, engagement with research and development and scientific wind energy communities is encouraged, such as with one of the tasks within the International Energy Agency’s Technology Collaboration Programme.
• To develop solutions for identifying, quantifying and/or reducing uncertainties in the outputs of selected wind energy analytical exercises (see example bulleted list in the above section) linked with motion of the floating offshore wind turbine.
• To build, develop and test methods and models using programming and software tools.
• Engage and liaise with experts across EDF group to further build on and refine knowledge and understanding.
• Engage with stakeholders and potential end users of research outputs within EDF Renewables business entities to ensure results have industry relevance.

Training and Skills

Depending on prior experience, you will be trained to use numerical packages (e.g., Matlab and Python). Further project-specific training will be defined when developing your training and self-development plan. The student will also have access to training courses and programmes provided by EDF which cover a diverse range of technical and soft skills.

With the CDT, 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 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.

CDT students enrol at the university where their doctoral research will be based. If your research will be based at Durham, Loughborough or Sheffield, you are able to access six-month University of Hull campus accommodation contracts, to cover the initial training period.

References

[1] Bastankhah, Majid, et al. “Analytical solution for the cumulative wake of wind turbines in wind farms.” Journal of Fluid Mechanics 911 (2021): A53.

[2] Bastankhah, M., Mohammadi M., Lees C., Navarro G., Buxton O., Ivanell S.. A fast-running physics-based wake model for a semi-infinite wind farm, Journal of Fluid Mechanics, under review, 2023

[3] Bastankhah, Majid, and Fernando Porté-Agel. “A new analytical model for wind-turbine wakes.” Renewable energy 70 (2014): 116-123.