含液颗粒材料液固耦合分析的离散颗粒模型及特征线SPH法

A discrete particle model and characteristic based SPH method for fluid-solid interaction of granular materials filled with liquids

对含液颗粒材料流固耦合分析建议了一个基于离散颗粒模型与特征线SPH法的显式拉格朗日-欧拉无网格方案。在已有的用以模拟固体颗粒集合体的离散颗粒模型[1]基础上,将颗粒间间隙内的流体模型化为连续介质,对其提出并推导了基于特征线的SPH法。数值例题显示了所建议方案在模拟颗粒材料与间隙流相互作用的能力和性能以及间隙流体对颗粒结构承载能力及变形的影响。

In the frame of discrete particle model for modeling of granular materials, there exist two main types of mathematical models for modelling interstitial liquid, i.e. the discrete （liquid-bridge） and continuum models. The liquid-bridge model is mainly used for low moisture content and is not able to model the fluid transport within a porous medium. To model fluid flow through a porous medium and its interaction with the solid grains of the medium, a continuum model should be employed. In this paper a coupled discrete particle-continuum model for wet granular materials is developed. The solid particles are described by discrete particle model, and the motion of the interstitial fluid phase and its interaction with the solid phase are described by continuum scheme governed by the averaged N-S equation. In light of SPH approach, the characteristic based SPH method is presented for numerical modeling of pore fluid flow. A numerical solution procedure based on discrete element method and characteristic based SPH for wet granular materials is formulated. Numerical results demonstrate the capability and performance of the proposed scheme in modeling the interaction and exhibit influences of interstitial fluid flow upon the loading capacity and deformation of the solid particle assembly.