Progresses in the Development of a Weakly-Nonlinear Wave Body Interaction Model Based on the Weak-Scatterer Approximation

Abstract

In continuation of [1], this paper presents the progress made towards the development of a new modeling tool based on the Weak-Scatterer approaches. 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 [2] and Cointe’s [3] formulations for the acceleration condition on the body are revisited. Numerical prediction with the present method for a submerged body in vertical free motion is presented and energy conservation is verified. In order to adapt the mesh to the moving body geometry, advanced mesh moving schemes have been integrated based on radial basis functions [4] 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 wave diffraction and radiation predicted by linear theory, a fully nonlinear BEM solver and the present method are shown.

Efficient Nonlinear Hydrodynamic Models for Wave Energy Converter Design—A Scoping Study

“…The WSA was pioneered by Pawlowski for nonlinear ship hydrodynamics in the early 1990s [178] but has only been applied to WECs in the past decade. The first usage is reported in Bretl [165] to assess the performance of a small scale data buoy equipped with an oscillating pendulum PTO, then in Merigaud et al [168] for a comparison against linear Cummins and NLFK models, and as then via the WSA code, under development at Ecole Central de Nantes (ECN) [170][171][172][179][180][181][182]. Letournel [179] developed a WSA model, for submerged bodies, and an early-stage comparison against an FNPF BEM solver is presented in [180], for the case of prescribed motion of a submerged cylinder, showing good agreement and roughly an order of magnitude speed increase.…”

“…Letournel [179] developed a WSA model, for submerged bodies, and an early-stage comparison against an FNPF BEM solver is presented in [180], for the case of prescribed motion of a submerged cylinder, showing good agreement and roughly an order of magnitude speed increase. The WSA model is extended to a surface piercing cylinder in Chauvigné et al [181], employing an ALE approach to adapt the mesh to the moving body geometry and free surface. In Bozonnet et al [171], the WSA model is then applied to a scaled Wavestar float, demonstrating similar results to experiments and an NLFK model.…”

Comparison Between Experiments and a Multibody Weakly Nonlinear Potential Flow Approach for Modeling of Marine Operations

“…Equations (8), (9), (10), (11) and (12) constitute the first Boundary Value Problem (BVP) to solve [11].…”

“…Letournel [11] developed a version for a single submerged body with translational motions. Chauvigné [12] extended it to a single surface-piercing body.…”