In this paper, particulate gas flows over a circular cylinder were studied numerically for wide ranges of flow Reynolds numbers (5 < Re < 5 x 10(6)) and P numbers (0.025 < P < 5 x 10(4)). P number is defined as 9Re/S and S is the particle-fluid density ratio. For Re <= 100, the laminar flow simulations were performed while the turbulent flow simulations were done for Re >= 10(3) using unsteady Reynolds-averaged Navier-Stokes (URANS) equations. The Reynolds stress model (RSM) was used to account for the anisotropic turbulent stresses around the cylinder. The computed drag was compared with the available experimental data and earlier numerical results. It was shown that the RSM could properly predict the drag-drop at the critical flow regime. Deposition of particles on the cylinder surface was also investigated using the Lagrangian trajectory analysis. Particle capture efficiencies were evaluated and compared with the available experimental data and theoretical models. The simulation results indicated that for P >= 10(2), the computed capture efficiencies obtained by the viscous flow analysis coincided with those obtained from the inviscid flows. For 1 <= P <= 10, differences between viscous and inviscid flow collection efficiencies, however, were more than 20% when Stk <= 1. However, for P <= 0.1, differences between the collection efficiencies obtained by viscous and inviscid flows exceeded 20% when Stk <= 2.2. In the case of Re=10(3) and P=10, the highest capture efficiency was obtained by impaction for Stk >= 0.5.