Centre National de la Recherche Scientifique
Site d'essais en mer de Centrale Nantes
Diverse experimental and numerical methods are used to address the scientific subjects covered by the group: physics of nonlinear gravity waves, interaction of floating or fixed marine structure with its environment, etc. Specific care is paid to regularly setting up digital twins of experiments conducted in the LHEEA facilities. As for the study of wave propagation, the objectives are to increase understanding of physical phenomena, to characterize extreme events of a given sea-state and to study the influence of wave breaking and wave directionality.
Another part of this research topic is dedicated to external forces acting on floating devices, especially for floating wind turbines. It relies in particular on CFD modeling including far wake effects, mooring and aerodynamic loads, and on corresponding experimental tests. Finally, hydrodynamic loads on floating structures in waves are also studied as part of this research topic. For instance, specific issues regarding floating wind turbines (low-frequency response, heave plates, etc.) are studied in collaboration with the SEM-REV+ research group. The performance analysis of ship in waves is the last component of the researches conducted, posing a number of challenges: stochastic feature requiring simulations over long times, wave directionality and presence of appendages requiring high-resolution meshes which are difficult to build and induce large simulation costs.
This research topic aims at increasing the knowledge of flows around deformable structures, in interaction or not with the free surface. In particular, it answers a societal need to develop flexible lifting structures, most often made of composites, allowing to optimize their performances through passive control strategies of their deformations/vibrations. Targeted applications are offshore wind turbines and marine propellers:
This research topic aims at developing mainly two kinds of methods:
This research topic aims at addressing the following physical problems and applications:
Innovative techniques are developed to allow model-scale reproduction of external forces, in particular integrating assisting the experiment with real-time numerical simulation.
Regarding marine propellers the objective is two-fold: i/ improving the test facility embedded in a circulation channel and consolidating its measuring system of the propeller performances, and ii/ validating flow visualization and velocity measurement techniques (LDV, PIV).
Finally, a new generic test bench to study the performances of flexible lifting profiles in the towing tank is under development.
The towing tank is 140 m-long, 5 m-wide, with a constant depth of 3 m. It is equipped with a towing carriage able to move in both directions, at speeds up to 8 m/s. At one end of the tank, a wave maker generates waves with heights up to 0.5 m.
50 m long by 30 m wide and 5 m deep, the tank is equipped with a segmented wave beater composed of 48 independent flaps to generate directional waves. This tank allows the simulated physical simulation of floating systems, navigating or anchored in open seas (ships, MRE systems or oil platforms).
This canal has a test vein of 2 m wide and about 10 m long. The maximum use depth of the basin is about 1.10 m. It is used for studies of marine propulsion systems, turbine performance, stationary flows and stabilization (appendages, foils, fins, etc.)
