A series of Euler–Lagrangian four-way coupling Large-Eddy Simulations (LES) are performed to study the dynamics of settling particle clouds. The numerical method is first validated by comparing with existing experimental results. Then, a parametric study is performed with various initial release shapes, particle sizes, and cloud buoyancies. Three issues are examined in detail, including the initial release aspect ratio, two-phase interactions and polydispersion. Incorporating these factors, empirical relationships are developed to predict the phase separation time and height, the position of the cloud front and the edge radius based on numerical results. The entrainment rate and deposition patterns are also analyzed. These relationships should be useful for engineering applications.