This study uses laboratory experiments and numerical simulation method to investigate the settling behavior of dual cube particles. Particle image velocimetry (PIV) was introduced in the experiments and smooth particle hydrodynamic (SPH) method was introduced in the numerical simulation. Cube particles with two diameters  , six initial spacings   are released side-by-side in a tank, and the range of Reynolds number   based on the terminal velocity, the viscosity of fluid and diameter of the particle is  . The fluid consists of a mixture of glycerin and water. The experimental and numerical results reveal that due to the difference of particle-fluid interactions, dual cube particles present larger repulsion than dual sphere particles, and the influence of the initial spacing   and Reynolds number   is clarified. The superposition of pressure difference and friction drives the settling behavior of dual cube particles, while only the pressure difference plays a key role in the settling behavior of dual sphere particles. Moreover, the relationship between settling behaviors and flow characteristics in the whole process of dual cube particles is further revealed. The spacing of dual cube particles first increases and then decreases, while the spacing of dual sphere particles increases gradually. The rotation of cube particles is the main factor of above differences, which changes the flow characteristics and the hydrodynamic around the particles.
 

Particle settlement,Particle interactions,Particle image velocimetry,Smooth particle hydrodynamic method