PhD – Breaking waves impact

On 10 April, Florian HULIN defended his thesis on the hydrodynamic loads induced by wave impacts on floating wind turbines. This work was carried out as part of the DIMPACT research project.

View selected footage of Florian Hulin’s defence


Breaking wave impacts may be responsible for the most severe hydrodynamic loads encountered during the life time of a floating offshore wind turbine, and significant progresses are required to predict these loads with confidence. We aimed to experimentally identify the different parameters of the waves and of the turbine which influence the impact
force and to quantitatively assess their importance. A segmented circular cylindrical mockup was used to measure the loads generated by focused breaking wave impacts. We used a new methodology based on a set of accelerometers to compensate for the force signal oscillations induced by the vibrations of the mockup, which are triggered by the impulsive nature of impact. An important effort was devoted to the characterisation of the impacting breaking waves in terms of geometry, crest speed and breaking strength. They were measured using a video camera and modelled with a fully non-linear potential flow solver. We investigated the influence of the breaking strength of the impacting waves, the distance between the breaking location and the front face of the cylinder, the tilt angle of the cylinder and the horizontal velocity of the cylinder during impact.

Composition of the jury

  • Guillaume DUCROZET, Professor – Ecole Centrale de Nantes
  • Laurent DAVID, Professor – Université de Poitiers
  • Grégory PINON, Professor – Université Le Havre Normandie
  • Deborah GREAVES, Professor – University of Plymouth
  • Nicolas JACQUES, Senior lecturer – ENSTA Bretagne
  • Alan TASSIN, Researcher – Ifremer
  • Jean-Francois FILIPOT, Scientific Director – France Energies Marines

Photo credit: Saskia 1310 / Pixabay

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