Correction And Application Of High Nonlinear SPH Hydrodynamic Model

Smooth particle hydrodynamics (SPH) is a meshfree lagrangian mehod for simulating fluid motion. Because of meshfree and self-satisfactory, SPH is suitable for flow problems which concludes mass deformation and complicated substance boundary. It can avoid the shortage in FDM and FEM method, such as mesh reformation, distortion and complicated boundary creation. With the development and correction of SPH method, it gradually becomes a research focus in computed fluid dynamics.Based on the basic theory of SPH, this paper uses CSPM and Riemann solver of sound approximately to correct the governing equations of fluid (mass consistence and N-S equations). To decrease the gradient of pressure between solid particles and around fluid particles, a new pressure calculation method is presented. A CSPM-R numerical model is established to calculated 2D free surface flow problems.A 2D non-reflection numerical tank is established based on the corrected CSPM-R model. An absorbing wavemaker boundary condition for particle method and layout of sponge layer is presented. The capability of absorbing second reflecting waves and incoming waves for absorbing wavemaker and sponge layer is validated through comparison with general wavemaker. The precision of CSPM-R model presented in this paper is validated through comparision of wave surface and pressure field at different locations calculated from CSPM-R model and original SPH method.Shoaling of solitary waves is analyzed in a numerical tank based on established CSPM-R model. The variation of wave surface is given together with the location, water depth and wave height of breaking waves.And simulated resultes are compared with experimental data. The characteristics of variation of wave surface during surging, plunging and spoiling.To avoid disorder of the fluid field around the structure due to wall particles when using wall particle mehod to simulate the boundaries of the structure, a new impacting boundary condition is presented. The effection of wave impacting on the platform is simulated usirng the CSPM-R numerical tank. The satisfactory of using this impacting boundary to simulate small clearance and thin platform impacting problems is validated to compare with the numerical result from wall particle structure treatment. The variation of fluid field and pressure distribution under the structure during the process of wave impacting are analyzed and compared with experimental result. The distribution of velocity and pressure along the water depth under the structure is discussed also. A 2D coupling numerical model of CSPM-R and DEM method is established. The interaction between regular wave and armour blocks on a slope is simulated. The armour blocks are simulated using DEM method. Fluid phase is simulated using CSPM-R model. A fluid-solid interface force condition is presented which is suitable for SPH and DEM method.The fluid pressure, interaction force between neibouring blocks and motion of block are calculated using the established CSPM-R-DEM coupling model. The characteristics of fluid field variation and the pressure dristribution along the armour blocks when wave moving along the slope are analyzed. The time series of wave impacting pressure on parapet is given and validated using experimental data.