In order to explore the applicability of different implementation methods for periodic boundary conditions involved in the open-source computational fluid dynamics software,by the name of OpenFOAM,numerical simulations on the Poiseuille flow in a circular pipe were performed,using mapped,cyclicAMI and cyclic fan boundary conditions,respectively.The numerically obtained velocity and pressure profiles were analyzed.The results show that the velocity profiles obtained under the three boundary conditions are in agreement with the analytical solution.Specifically,the results under the mapped and cyclicAMI boundary conditions,which are very close to each other,agree better with the analytical solution.The pressure profile obtained under the mapped boundary condition is in good agreement with the analytical solution,whereas there are large pressure gradients at the inlet and outlet of the simulation domain when the cyclic fan boundary condition is adopted.Moreover,the pressure along the pipe axis is always zero under the cyclicAMI boundary condition.On this basis,the sensitivity of the numerical simulation results to the computational cell was examined.It is found that as the cell number along the pipe diameter increases,the computational accuracy of the velocity increases rapidly and then becomes stable.The increase of the number of boundary layers can effectively improve the computational accuracy of the velocity near the wall.Furthermore,more than 16 cells along the diameter and not less than 3 boundary layers are necessary for numerical simulations.