PhD Defense - Marion Huchet - LHEEA/ED SPI

Title:

" Deterministic sea wave prediction using velocity profile measurements "

Jury:

The defence will be held in French in front of a jury composed of:
- Laurent DAVID (Université de Poitiers) - Rapporteur
- Marissa YATES (CEREMA) - Rapporteur
- Stéphan GRILLI (Université de Rhode Island) - Examinateur
- Pierre FERRANT (Centrale Nantes) - Directeur de thèse
- Guillaume DUCROZET (Centrale Nantes) - Co-encadrant
- Jean-Christophe GILLOTEAUX (Centrale Nantes) - Co-encadrant

Abstract:

This PhD thesis presents a new method for deterministic sea wave prediction, able to accurately describe the evolution of nonlinear sea states while keeping the computation time reasonable. Particular attention is paid to the quality of the wave phase information. Contrary to classical approaches relying on free surface elevation measurements, information on the incident sea state is collected here in the form of instantaneous horizontal wave velocity profiles upstream of the area of interest. This kinematic information is used in a nonlinear propagation model based on a pseudo-spectral approach, allowing to avoid the data assimilation step usually required in this kind of model. This greatly reduces the computation time while
maintaining the prediction quality. This work presents a feasibility study of this method for long-crested waves. In the lack of an instrumentation dedicated to the measurement of instantaneous horizontal velocity profiles, an original method is developed to reconstruct this information from acoustic Doppler current profiler (ADCP) measurements, thus extending the current application scope of these sensors. Numerical sensitivity studies then evaluate the quality of the prediction obtained for various measurement configurations and sea states. Lastly, we present the trials conducted in Centrale Nantes' towing tank, which provide an experimental validation of the method for unidirectional waves. The good numerical and
experimental results obtained make this method a promising approach.

Visioconference

The thesis defense will take place on Zoom:

https://ec-nantes.zoom.us/j/93816685678
Password: HrR$CG8g

In order to lighten the bandwidth, all participants will be asked to switch off their camera and microphone throughout the presentation. Finally, we thank you to connect around 14:15 am or earlier in order to have time to manage any technical problems before starting the defense. Thanks to all of you!

A limited number of place will be available in Lecture Theater E.