Pierre Lubin

THREE-DIMENSIONAL LARGE EDDY SIMULATION OF VORTICES INDUCED BY PLUNGING BREAKING WAVES

The scope of this paper is to show the results obtained for simulating 3D plunging breaking waves by solving the Navier-Stokes equations in air and water, coupled with a subgrid scale turbulence model. The breaking processes including overturning, splash-up and breaking induced vortex-like motion beneath the surface are presented and discussed. Plunging breaking waves have been simulated in periodic domains and compared with previous published works. We found a very good agreement with the general description we could find in the literature concerning the breaking processes.

LARGE EDDY SIMULATION OF REGULAR WAVES BREAKING OVER A SLOPING BEACH

The scope of this paper is to show the results obtained for the Large Eddy Simulations (LES) of three-dimensional regular waves shoaling and breaking over a sloping beach, by solving the Navier-Stokes equations in air and water. The interface tracking is achieved by a Lax-Wendroff TVD scheme, which is able to handle with interface reconnections. The breaking processes including shoaling, overturning, splash-up and air entrainment, will be presented and discussed.

Local Mesh Refinement and Penalty Methods Dedicated to the Direct Numerical Simulation of Incompressible Multiphase Flows

Recent advances in numerical methods for the direct numerical simulation (DNS) of multiphase flows are presented. The mathematical formulation is based on an eulerian discretisation of the navier-stokes equations on fixed staggered curvilinear grids where the media are located thanks to volume of fluid functions. An adaptative and local mesh refinement method (AMR) is proposed to allow multi-space scale solutions in three dimensions and a tensorial penalty (or fictious domain) approach is detailed for the numerical modelling of incompressibility, velocity/pressure coupling and liquid/solid interactions in multi fluid flows. The article is focussed on three-dimensional applications of the direct numerical simulation. The DNS tool is applied to the mould filling under unstable viscous jet conditions, the stoke’s flow induced by a solid particle in a tube and the turbulent wave breaking in deep water. These flows are chosen to highlight the abilities of the numerical model for characterising unsteady incompressible multiphase flows.Copyright

Simulation numérique du phénomène de franchissement d'ouvrage par une houle irrégulière

Résumé : Dans le cadre du projet EMACOP (Énergie MArine CÔtière et Portuaire, http://www.emacop.fr/), une étude numérique est réalisée afin de tester la validité dun modèle Navier-Stokes/VOF pour la simulation du processus de franchissement intervenant sur des systèmes de récupération d’énergie marine. Dans larticle, nous présentons la méthode numérique utilisée pour générer une houle irrégulière, puis nous étudions différents cas de franchissement dun obstacle incliné par une houle irrégulière. Les volumes de franchissement simulés sont comparés aux mesures expérimentales disponibles dans la littérature. Mots-clés : Simulation Navier-Stokes, Débits de franchissement, Energie de la houle, Houle irrégulière.