Numerical Simulation of Unsteady Flow around an Environmental Square Cylinder

The flow field characteristics around a square cylinder determine particle concentration distribution in environmental air. This paper introduces the application of the numerical simulation in the research of flow around an environmental square cylinder, improves the numerical simulation method, and uses the Unsteady Reynolds-average Numerical Simulation (URANS) to research the flow around an environmental square cylinder. Result shows that unsteady RANS k-ε model achieved a better conclusion than the steady simulation. In the numerical simulation of the flow around a square cylinder, especially in the simulation of the Karman vortex at the end of the square cylinder, the unsteady RNG k-ε model clearly shows the fall-off and reattachment process of eddy; and the result in same phase matches well with the average result achieved by the large eddy simulation. Compared with the large eddy simulation, the calculation results using URANS are more close to experiment results in separation-points-fixed circular square cylinder. This paper will be an essential basis for practical applications.