• PhD,

PhD Defense - Wenjin CAO - ED SPI

"Investigation of the applicability of the lattice Boltzmann Method to free-surface hydrodynamic problems in marine engineering"

On April 8, 2019 from 14:00 To 16:00

On April 8, 2019 from 14:00 To 16:00

Supervisor: David LE TOUZE

Laboratory: LHEEA

Monday 8 April 2019 at 2 pm at Centrale Nantes, Lecture Theatre S

Abstract:

The numerical simulation of the free-surface flows for marine engineering applications is a very challenging issue in the field of computational fluid dynamics (CFD). In this thesis, we propose a solution, which is to use the regularized lattice Boltzmann method (RLBM) with a volume-of-fluid (VOF) based single-phase free-surface lattice Boltzmann (LB) model, and we investigate its feasibility and its reliability.
The theoretical insights of the lattice Boltzmann method (LBM) are given at first, through the Hermite expansion and the Chapman-Enskog analysis. From this perspective, the idea of the RLBM is summarized as the Hermite regularization of the distribution functions. On the test-cases of the Taylor-Green vortex and the lid-driven cavity flow, the RLBM is verified to have a 2nd-order accuracy and an improved stability.
The adopted free-surface model is then implemented into the RLBM and validated through simulating a viscous standing wave and a dambreak flow problems. It is shown that the regularization not only strongly stabilizes the calculation by reducing spurious pressure oscillations, which is very beneficial for obtaining accurate free-surface motions, but also does not introduce any extra numerical dissipation.
Furthermore, a new reconstruction method for the distribution functions at the free-surface is proposed. The present model is more consistent with the RLBM, which provides an effective way for simulating high-Reynolds-number free-surface flows in marine engineering.

Keywords: marine engineering, LBM, free-surface, regularization

Jury:

M. DE VUYST Florian, Professeur des universités, Université de Technologie de Compiègne
M. DUBOIS François, Professeur des universités, Conservatoire National des Arts et Métiers, Paris
M. FAVIER Julien, Maître de conférences, Université Aix-Marseille
Mme GINZBURG Irina, Chargé de recherche HDR, IRSTEA, Antony
M. LE TOUZÉ David, Professeur des universités, École Centrale de Nantes
M. LI Zhe, Maître de conférences, École Centrale de Nantes
Published on March 22, 2019 Updated on April 4, 2019