數値流體解析에 있어서 SPH法의 適用

Abstract

Smoothed Particle Hydrodynamics(SPH) method is one of meshless methods using the particle, which is different from previous methods using the mesh. This method uses smoothed particles as interpolation points to represent materials at discrete locations, so it can easily trace material interfaces, free surfaces and moving boundaries due to large deformations since SPH uses particles or points rather than mesh as computational frame to interpolate. Fundamentally, SPH method is based the continuity equation and momentum equation by SPH approximation. To analyze the incompressible and viscous Fluid, this method is used the artificial equation and state equation. The equation of boundary condition proposed by Monaghan(1994) for distinguishing between fluid and boundary particles is used. The discrete SPH equation can be integrated with leap-frog method scheme. In this study, two kinds of numerical simulation by SPH method is carried out. First of all, it is simulated about water column collapse and the result is compared with Martin and Moyce's experimental data and the result of MPS and SMAC method. And a good result is obtained. The sensitive analyses on the time step(), artificial viscosity -term and particle number are performed. It is presented that the controlling these term is related to the efficiency and accuracy of the numerical simulation, and the phenomenon of water column collapse by using the particle and velocity vector is also visualized. Secondly, the numerical simulation about solitary wave propagation using SPH method is carried out. The results of maximum wave runup on a vertical and slope wall obtained this simulation are compared with the experimental data and are obtained good results. For the more detail comparison, water surface profile on a slope wall is also compared in detail with experimental data and is obtained a good agreement. The results through particle configuration and velocity distribution at various times are visualized. It is shown to be capable of simulating about sloshing phenomena of a solitary wave propagation, runup, rundown and backwash. Finally, it is shown that this method could be applied to the breaking phenomenon of hydraulic structures such as dam break and the model of ocean waves like tsunami or storm surge.