Particle settling is one of the basic topics of sediment kinematics, as well as the basis of environmental sedimentology. In this paper, the settling process of multiple spherical particles in a horizontally arrangement is investigated experimentally and numerically simulated. In the experiments, the previously invented particle electromagnetic release device is used to achieve synchronous and no initial velocity release of particles to ensure that the initial conditions are strictly controllable. The effects of settling time, number of particles, and initial configuration of particle group on the settling process are investigated in detail. In the numerical simulation, the Smoothed Particle Hydrodynamics method (SPH) was used to investigate the flow field around the particles and the pressure distribution. The results show that repulsion occurs between particles during the settling process. and the settling process can be divided into 2 stages. The repulsion always follows the rotational motion of the particles, with the outer particles rotating outward and the inner particles rotating inward. The total repulsive distance has a low correlation with the number of particles when the particles don't collide with each other, whereas the inter-particle interactions are inversely proportional to the number of particles. The average settling velocity of multiple particles is basically the same as that of the single particles.
 

Steady pattern,Multi-particle settling,Hydrodynamic interaction,Initial configuration,Particle Tracking Velocimetry