Improvement of the precision and the efficiency of the SPH method: theoretical and numerical study

Computational fluid mechanics experienced in the last decades a fast development with the creation and improvement of numerical methods. The SPH (Smoothed Particle Hydrodynamics) method has emerged as an alternative to traditional methods for treating violent flow with a complex free surface, which made it very interesting to reproduce problems in the field of naval engineering. This method raised interest in the academia and in the industry and, lately, has progressed rapidly, reaching a state of almost-maturity. In this context, after a presentation of the method's state of the art, three different tracks for improvement are presented. The first studies a completely incompressible approach from which a new method to treat incompressibility is developed, validated and applied. This new method has shown to be effective and accurate. The second area of research focused on the space discretization of the fluid domain. Since the SPH method is of Lagrangian nature, it is difficult to adjust the particles' distribution to the characteristics of the flow that is being treated, which requires a dynamic approach. Existing refinement methods from the literature were reviewed and a new technique that allows to dynamically derefine particle distributions was proposed. The effectiveness of the SPH method was thus improved. Eventually, in order to improve the accuracy of the operators used in the SPH method and to increase its convergence order, the coupling between a Lagrangian finite volume method and SPH is proposed. This led to a better understanding of the SPH method and opens a new area of research: hybrid SPH methods.