Postdoctoral position available in the LHEEA on "full-scale experimental validation of realtime deterministic wave prediction applied to floating wind turbines"

Work description

Phase-resolved wave prediction is an active research topic in recent years. At Centrale Nantes, among other works, earlier experimental and numerical developments [1, 2, 3] conducted by the implied research team focused on defining the relevant wave model to achieve a given level of accuracy for a target prediction horizon in a controlled environment. A postdoctoral fellow at ECN (also part of the FLOATECH project) is currently working on the improvement of the prediction algorithms. Then, the present position will include a close collaboration with this researcher.

A next level in readiness is now required, and a work plan has been built through FLOATECH project to deliver an experimental database from a full-scale setup. NextOcean wave prediction system, including an X-band radar, is ready to be installed on Floatgen in order to capture the evolution of wave field surrounding the floating wind turbine. Once installed, the system will be run and exploited over the course of the project. Synchronous measurements from a waverider buoy moored on site, in the vicinity of the FWT, will be acquired, and complementary sensors will be deployed per campaigns in order to provide a full set of deterministic local reference measurement of waves and surrounding environment in the observation field. Synchronous measurements of platform motions will be acquired on Floatgen.

Data analysis and off line validations will then be performed on a representative set of cases. It will consist in comparing the prediction made on the basis of remote measurements complemented by the wave buoy on the floater responses to the actual measurements performed on board. The accounting for hydrodynamic forcing will be performed through the Floatgen modelling chain already validated on measurements on a first account, but complementary approaches combining physical accounting as well as optimal fitting and data processing can be envisioned. Overall, the data set created will enable to ensure robustness and efficiency of the prediction method for future operational usage. According to the progress of the work, the postdoctoral researcher will be able to work on complementary tasks relevant with the overall objectives of the project and his background. For instance: sensitivity of the wave predication algorithm to the background tidal current and bathymetry on site, to spectral content, response of the floater, etc.

The position is available for 18 months, with a possible extension upon performance and funding.

Objectives / Expected results

• Construction of an experimental database in real conditions, applicable to the validation of deterministic wave prediction and aimed at feeding a floating wind turbine controller
• Validation of X-band radar sensing capability with respect to in situ conditions (wave, currents, wind, etc.)
• Exploitation of wave prediction algorithm against measurements
• Work in a collaborative environment through the active participation to international consortia.
• Write project reports and deliverables in line with EU expectations
• Write scientific publications

Technical skills and knowledge

Required qualifications are related to:

• PhD in Ocean Engineering, Fluid Dynamics, or Physical Oceanography with background knowledge of wave mechanics
• Knowledge of the marine environment is mandatory
• Experience in experimental campaigns and data analysis
• Good knowledge of a scientific language (Python, Fortran, matlab, …)
• Interest in ocean engineering problems

Personal qualities:

• Autonomous and dynamic
• Ability to interact with researchers working on numerous and varied research topics

References

[1] Desmars, N., Bonnefoy, F., Grilli, S. T., Ducrozet, G., Perignon, Y., Guérin, C. A., & Ferrant, P. (2020). Experimental and numerical assessment of deterministic nonlinear ocean waves prediction algorithms using non-uniformly sampled wave gauges. Ocean Engineering, 212, 107659.
[2] Guérin, C. A., Desmars, N., Grilli, S., Ducrozet, G., Perignon, Y., & Ferrant, P. (2019). An improved Lagrangian model for the time evolution of nonlinear surface waves. Journal of Fluid Mechanics, 876, 527-552.
[3] Desmars, N., Pérignon, Y., Ducrozet, G., Guérin, C. A., Grilli, S. T., & Ferrant, P. (2018, June). Phaseresolved reconstruction algorithm and deterministic prediction of nonlinear ocean waves from spatiotemporal optical measurements. In ASME 2018 37th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers Digital Collection.

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