Coordinateurs du projet
Context
The HP_Flow project, winner of the WEAMEC International Research Call for Projects, focuses on the hydrodynamic modeling of heave plates for floating wind turbines (anti-pitching plates) and is linked to the H2020 FLOAWER project.
Many floating foundation designs for floating offshore wind turbines use hydrodynamic damping devices called “heave plates.” These devices are generally flat horizontal plates installed at the bottom of the floating foundations and with a diameter greater than the foundation itself. These plates dampen the pounding and pitching movements of the entire structure by increasing radiation damping and the presence of vortex shedding. These plates also significantly increase the added water mass, thereby shifting the natural pounding and pitching periods beyond the predominant wave periods.
Scientific breakthroughs and innovation
The hydrodynamic behavior of heave plates (anti-pitching plates) is generally taken into account in standard design tools through empirical formulations based on coefficients obtained from tank tests or CFD simulations. The values of these coefficients are not always representative of the configurations tested, as they are taken from literature dedicated to offshore oil, which presents problems that are relatively distant from those of floating offshore wind power (larger diameter of heave plates, greater movement of structures, lower draft, etc.).
The objective of the HP_Flow project is both to model the hydrodynamics of heave plates for floating wind turbines and to conduct tank tests on various generic floating supports representative of those used in floating wind turbines, in order to obtain a database that will be used in other projects to validate numerical models and to refine existing numerical models.
Expected technical and economic impact
The impact of the project will be reflected in:
- advances in knowledge of the behavior of heave plates and the physical mechanisms governing their responses to wind turbine movements and waves;
- the development of recommendations for the design of heave plates;
- the creation of an open database to facilitate the design of floating systems;
- the strengthening of the partners’ international reputation and visibility in the field of floating wind power;
- annual presentations at international conferences in the sector (OMAE, DeepWind, IOWTC, etc.);
- the publication of articles in leading scientific journals.
Results
The main objective of the HP_Flow project is to conduct basin tests on semi-submersible foundation columns equipped with a heave plate. The tests consist of forced motion tests and tests in the presence of waves.
The first year of the project was devoted to defining and designing the experimental apparatus. Initially, a literature review was conducted on the standard dimensions of heave plates proposed in the literature on floating wind turbines. A second literature review focused on tank tests dedicated to the behavior of heave plates. The results of these two literature reviews led to the selection of four original and relevant geometric configurations for the creation of a database.
The design work for the entire experimental setup was then carried out. This setup will consist of a tripod installed in the center of the LHEEA ocean engineering basin, on which a hexapod will be installed to hold the models. A set of measuring devices consisting of wave sensors, force balances, accelerometers, and strain gauges was also defined. The tests are scheduled to take place in March 2022.