The present work deals with the numerical investigation for a chain-like formation of suspended particles of circular shape in fluid flow. An explicit volume integral approach for the calculation of hydrodynamic forces acting on the particle’s surface is used. A collision strategy proposed by Glowinski, Singh, Joseph and coauthors for the treatment of colliding or approaching particles is used. The direct simulation technique (fictitious boundary method) achieves the solution of incompressible flow along with moving rigid bodies. The Eulerian based approach which is independent of particle size, particle shape and number of particles is adopted to solve the fluid-particle phenomena in the computational domain. The fluid domain consisting of a multigrid finite element background is considered and the whole numerical process is carried out through open source code FEATFLOW. Numerical experiments for settling particles which are close together forming chain like formations are performed and analyzed. The study is carried out using different configurations of particle positions resulting in different chain patterns. Consequences of such patterns on particles’ motion and on the fluid-particle system is discussed.

中文翻译：

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通道中沉降颗粒链的数值研究

本工作涉及流体流动中圆形悬浮颗粒的链状形成的数值研究。使用显式体积积分方法来计算作用在粒子表面的流体动力。使用了Glowinski，Singh，Joseph和合著者提出的碰撞策略，用于处理碰撞或接近的粒子。直接模拟技术（虚拟边界方法）可以解决不可压缩的流动以及运动的刚体。采用与颗粒大小，颗粒形状和颗粒数量无关的基于欧拉的方法来解决计算域中的流体颗粒现象。考虑了由多网格有限元背景组成的流体域，整个数值过程通过开源代码FEATFLOW进行。进行并沉降了使彼此靠近而形成链状结构的颗粒沉降的数值实验。该研究是使用不同的颗粒位置构型进行的，从而产生不同的链型。讨论了这种模式对粒子运动和流体-粒子系统的影响。