Simulations of two-dimensional (2D) flow past a circular cylinder with the smoothed particle hydrodynamics (SPH) method were conducted in order to accurately determine the drag coefficient.The fluid was modeled as a viscous liquid with weak compressibility.Boundary conditions,such as a no-slip solid wall,inflow and outflow,and periodic boundaries,were employed to resemble the physical problem.A sensitivity analysis,which has been rarely addressed in previous studies,was conducted on several SPH parameters.Hence,the effects of distinct parameters,such as the kel choices and the domain dimensions,were investigated with the goal of obtaining highly accurate results.A range of Reynolds numbers (1-500) was simulated,and the results were compared with existing experimental data.It was observed that the domain dimensions and the resolution of SPH particles,in comparison to the obstacle size,affected the obtained drag coefficient significantly.Other parameters,such as the background pressure,influenced the transient condition,but did not influence the steady state at which the drag coefficient was determined.