Numerical investigation of three-dimensional flow over dual particles during settling

This study investigates three-dimensional flow over dual particles at various separation distances and Re, mainly focusing on the particle's lift behavior in close proximity. Minimal changes in separation distance can result in various unique flow patterns and a non-linear augmentation in lift coefficient. Additionally, quantifying flow blockage between two particles suggests that repulsion behavior and blockage phenomenon are not mutually inclusive. Transient simulations suggest that periodic vortex shedding is not only a function of Re and separation distance, but they also suggest the existence of multiple combinations of separation distance and Re at which the shedding mechanism is triggered. Evident periodic vortex shedding was quantified at 0.25D and Re = 250, while miniature periodic instabilities at the same Re but for a larger separation distance (0.5D). An observable inverse relationship between lift and separation distance exists, while different patterns were quantified for the variation of lift at different Re.