应用PISO算法及非交错斜交网格技术，编制了求解二维定常、非定常流动的通用程序。计算分析了定常不可压缩Couette流动以及水平通道内方柱绕流尾迹的非定常流动，并详细分析了不同时刻方柱后尾迹的旋涡结构及发展过程，得到了合理的结果。验证了非迭代PISO算法及非交错斜交网格在分析非定常流动中的有效性，为进一步开展非定常流动的数值分析奠定了基础． By using PISO algorithm and non-staggered skewed grid technique, a general program for solving two-dimensional steady and unsteady flow was developed. The steady incompressible Couette flow and the unsteady flow around the wake of the square column in the horizontal channel were calculated and analyzed. The vortex structures and development process of the tail vortex at different time were analyzed in detail and the reasonable results were obtained. The validity of non-iterative PISO algorithm and non-staggered bias grid in analyzing unsteady flow is verified, which lays the foundation for further numerical analysis of unsteady flow.