Survey on Smoothed Particle Hydrodynamics and the Particle Systems <s> 2) IMPROVED COUPLING BOUNDARY METHOD <s> This paper presents a study based on the smoothed particles hydrodynamics (SPH) method, aiming at an accurate numerical simulation of solid-fluid coupling in a free surface flow context. The SPH scheme is first described and discussed through its formulations. Then a new technic based on a particle sampling method, and designed to evaluate fluid pressure on solid boundaries is introduced. This method is then extended to the capture of freely moving body dynamics in a fluid/solid coupling approach. This study involves a spatially varying resolution, based on the so-called variable smoothing length technique, for which a new formulation of the equations is proposed. Two distinct test cases of wedge water entry are presented in order to validate this new method. Pressure prediction is first compared with analytical and experimental results, evolution in time of the body dynamics is compared with experimental results in both cases, and the pressure field on the solid boundaries is studied and discussed on the first impact case. <s> BIB001 </s> Survey on Smoothed Particle Hydrodynamics and the Particle Systems <s> 2) IMPROVED COUPLING BOUNDARY METHOD <s> An improved boundary treatment approach for smoothed particle hydrodynamics(SPH) method is presented.The pressure of a boundary particle is obtained by interpolation using the pressure of fluid particles in the near boundary area around it,and the boundary particle pressure is used in solving the momentum equations.This boundary treatment is implemented in the SPH model for two dimensional hydrodynamic flows with the free surfaces particularly at the violent deformation and breaking of it.The nonlinear sloshing in a rectangular tank and water entry of a wedge are simulated for model validation.It turns out that,for the case of sloshing,the free surface elevation at a wave probe is in good agreement with the experimental results.The computed values of pressure distribution along the surface of wedge coincide with the experimental data.It shows that this approach of boundary treatment works well for SPH models. <s> BIB002
The pressure on a boundary point obtained by solving the continuous and state equations is not a matter of true pressure. In response to this deficiency, Gong et al. BIB002 improved the method of solving particle pressure, in which the pressure was obtained by setting a pressure interpolation for fluid particles. Thus, the problem that the original coupling boundary method is not allowed has been improved on the boundary. The boundary pressure interpolation method was improved owing to the interpolation method proposed by Oger et al. BIB001 .