Domain size effects on particle microstructures settling in non-Stokes regime

Monodisperse particles in settling is studied using particle resolved direct numerical simulations. Inter particle and fluid interactions are modeled using immersed boundary method and inter-particle interactions are modeled using soft sphere discrete element method. It is observed both velocity fluctuations and particle microstructures can be affected by size of domain for smaller settling Reynolds number and volume fraction of particles. For finite settling Reynolds number of particles (Re >= 10); the variance of fluctuations of particles velocity saturates at some constant value by increasing the domain size due to wake-induced interactions between particles.