Progresses in the developement of a weakly-nonlinear wave body interaction model based on the weak-scatterer approximation

Camille Chauvigné (1) , Lucas Letournel (1) , Aurélien Babarit (1) , Guillaume Ducrozet (1) , Pauline Bozonnet (2) , Jean-Christophe Gilloteaux (1) , Pierre Ferrant (1)

1 LHEEA - Laboratoire de recherche en Hydrodynamique, Énergétique et Environnement Atmosphérique
2 IFPEN - IFP Energies nouvelles

Recent development in wave energy converter technology brings some new challenges in fluid structure interaction modeling and seakeeping analysis. Designs and dimensions of oscillating wave energy systems imply that the amplitude of their motion response will be large. [2]. Usual approach based on linear wave theory is not well-suited in this case because they are limited to small amplitude because of the linearity assumptions. In principle, CFD codes are able to deal with large amplitude motion response, but their computational cost is still too expensive for design purpose [3]. Combining non linear features and computational efficiency of BEM approaches, the Weak-Scatterer [4] approximation is believed to be a promising alternative [5]. In the continuity of [5], this paper presents (i) the progresses made towards the development of a new modeling tool based on the Weak-Scatterer approaches and (ii) quantitative comparisons of numerical prediction using usual linear theory vs the present approach for a submerged heaving wave energy converter. Recent developments are the coupling of the fluid and body solver in order to predict the free motion response of the body. Pressure field over the wetted area is obtained by solving an additional boundary value problem for the time derivative of the velocity potential. Tanizawa’s [6] and Cointe’s [7] formulations for the acceleration condition on the body are revisited. The solver is verified by energy conservation considerations. In order to adapt the mesh to the moving body geometry, advanced mesh moving schemes have been integrated based on radial basis functions [1] and spring analogy methods. In this way it is possible to solve the problem with an Arbitrary Euler Lagrangian formalism and preserve the order of the numerical scheme. However moving mesh methods are limited in time and automatic remeshing generation algorithms have been integrated in order to enable simulating longer durations. Finally, comparisons of the body response predicted by a fully linear BEM solver and the present method are shown.

Domaines: Mécanique des fluides [physics.class-ph]; Energie électrique

Camille Chauvigné, Lucas Letournel, Aurélien Babarit, Guillaume Ducrozet, Pauline Bozonnet, et al.. Progresses in the developement of a weakly-nonlinear wave body interaction model based on the weak-scatterer approximation. ASME 2015 International Conference on Ocean, Offshore and Artic Engineering (OMAE2015), May 2015, St John's, Canada. ⟨10.1115/OMAE2015-41971⟩. ⟨hal-01198816⟩